Apple OS X 10.13 Security Technical Implementation Guide
| Version 1 Release 1 |
| 2018-09-28 |
| U_Apple_OS_X_10-13_STIG_V1R1_Manual-xccdf.xml |
| This Security Technical Implementation Guide is published as a tool to improve the security of Department of Defense (DoD) information systems. The requirements are derived from the National Institute of Standards and Technology (NIST) 800-53 and related documents. Comments or proposed revisions to this document should be sent via email to the following address: disa.stig_spt@mail.mil. |
Vulnerabilities (134)
The macOS system must conceal, via the session lock, information previously visible on the display with a publicly viewable image.
Discussion
A default screen saver must be configured for all users, as the screen saver will act as a session time-out lock for the system and must conceal the contents of the screen from unauthorized users. The screen saver must not display any sensitive information or reveal the contents of the locked session screen. Publicly viewable images can include static or dynamic images such as patterns used with screen savers, photographic images, solid colors, a clock, a battery life indicator, or a blank screen.
Fix Text
This setting is enforced using the "Login Window Policy" configuration profile.
Check Content
To view the currently selected screen saver for the logged-on user, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep loginWindowModulePath If there is no result or defined "loginWindowModulePath", this is a finding.
The macOS system must be configured to disable hot corners.
Discussion
Although hot corners can be used to initiate a session lock or launch useful applications, they can also be configured to disable an automatic session lock from initiating. Such a configuration introduces the risk that a user might forget to manually lock the screen before stepping away from the computer. A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
To check if the system is configured to disable hot corners, run the following commands: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep wvous If the return is null, or does not equal: "wvous-bl-corner = 0; wvous-br-corner = 0; wvous-tl-corner = 0; wvous-tr-corner = 0;" this is a finding.
The macOS system must be configured to prevent Apple Watch from terminating a session lock.
Discussion
Users must be prompted to enter their passwords when unlocking the screen saver. The screen saver acts as a session lock and prevents unauthorized users from accessing the current user's account.
Fix Text
This setting is enforced using the “Restrictions Policy" configuration profile.
Check Content
To check if the system is configured to prevent Apple Watch from terminating a session lock, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep "allowAutoUnlock = 0;" If there is no result, this is a finding.
The macOS system must initiate a session lock after a 15-minute period of inactivity.
Discussion
A screen saver must be enabled and set to require a password to unlock. The timeout should be set to 15 minutes of inactivity. This mitigates the risk that a user might forget to manually lock the screen before stepping away from the computer. A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock.
Fix Text
This setting is enforced using the "Login Window Policy" configuration profile.
Check Content
To check if the system has a configuration profile configured to enable the screen saver after a time-out period, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep loginWindowIdleTime The check should return a value of "900" or less for "loginWindowIdleTime". If it does not, this is a finding.
The macOS system must retain the session lock until the user reestablishes access using established identification and authentication procedures.
Discussion
Users must be prompted to enter their passwords when unlocking the screen saver. The screen saver acts as a session lock and prevents unauthorized users from accessing the current user's account.
Fix Text
This setting is enforced using the "Login Window Policy" configuration profile.
Check Content
To check if the system will prompt users to enter their passwords to unlock the screen saver, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep askForPassword If there is no result, or if "askForPassword" is not set to "1", this is a finding.
The macOS system must initiate the session lock no more than five seconds after a screen saver is started.
Discussion
A screen saver must be enabled and set to require a password to unlock. An excessive grace period impacts the ability for a session to be truly locked, requiring authentication to unlock.
Fix Text
This setting is enforced using the "Security and Privacy Policy" configuration profile.
Check Content
To check if the system will prompt users to enter their passwords to unlock the screen saver, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep askForPasswordDelay If there is no result, or if "askForPasswordDelay" is not set to "5.0" or less, this is a finding.
The macOS system must monitor remote access methods and generate audit records when successful/unsuccessful attempts to access/modify privileges occur.
Discussion
Frequently, an attacker that successfully gains access to a system has only gained access to an account with limited privileges, such as a guest account or a service account. The attacker must attempt to change to another user account with normal or elevated privileges in order to proceed. Auditing successful and unsuccessful attempts to switch to another user account and the escalation of privileges mitigates this risk. Satisfies: SRG-OS-000032-GPOS-00013, SRG-OS-000064-GPOS-00033, SRG-OS-000462-GPOS-00206
Fix Text
To ensure the appropriate flags are enabled for auditing, run the following command: /usr/bin/sudo sed -i.bak '/^flags/ s/$/,lo/' /etc/security/audit_control; /usr/bin/sudo /usr/sbin/audit -s A text editor may also be used to implement the required updates to the "/etc/security/audit_control" file.
Check Content
To view the currently configured flags for the audit daemon, run the following command: /usr/bin/sudo /usr/bin/grep ^flags /etc/security/audit_control Attempts to log in as another user are logged by way of the "lo" flag. If "lo" is not listed in the result of the check, this is a finding.
The macOS system must implement DoD-approved encryption to protect the confidentiality and integrity of remote access sessions including transmitted data and data during preparation for transmission.
Discussion
Without confidentiality and integrity protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. Remote access is access to DoD non-public information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Encryption provides a means to secure the remote connection to prevent unauthorized access to the data traversing the remote access connection (e.g., Remote Desktop Protocol [RDP]), thereby providing a degree of confidentiality. The encryption strength of a mechanism is selected based on the security categorization of the information. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190
Fix Text
To enable the SSH service, run the following command: /usr/bin/sudo /bin/launchctl enable system/com.openssh.sshd The system may need to be restarted for the update to take effect.
Check Content
For systems that allow remote access through SSH, run the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.openssh.sshd If the results do not show the following, this is a finding. "com.openssh.sshd" => false
The macOS system must be configured to disable rshd service.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The "rshd" service must be disabled.
Fix Text
To disable the "rshd" service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.rshd The system may need to be restarted for the update to take effect.
Check Content
To check if the "rshd" service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.rshd If the results do not show the following, this is a finding: "com.apple.rshd" => true
The macOS system must enforce requirements for remote connections to the information system.
Discussion
The Screen Sharing feature allows remote users to view or control the desktop of the current user. A malicious user can take advantage of screen sharing to gain full access to the system remotely, either with stolen credentials or by guessing the username and password. Disabling Screen Sharing mitigates this risk.
Fix Text
To disable the Screen Sharing service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.screensharing The system may need to be restarted for the update to take effect.
Check Content
To check if the Screen Sharing service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.screensharing If the results do not show the following, this is a finding: "com.apple.screensharing" => true
The macOS system must be configured with Bluetooth turned off unless approved by the organization.
Discussion
The Bluetooth kernel extension must be disabled, as wireless access introduces unnecessary security risks. Disabling Bluetooth support with a configuration profile mitigates this risk.
Fix Text
This setting is enforced using the "Bluetooth Policy" configuration profile.
Check Content
If Bluetooth connectivity is required to facilitate use of approved external devices, this is not applicable. To check if Bluetooth is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep DisableBluetooth If the return is null or is not "DisableBluetooth = 1", this is a finding.
The macOS system must be configured with Wi-Fi support software disabled.
Discussion
Use of Wi-Fi to connect to unauthorized networks may facilitate the exfiltration of mission data. Satisfies: SRG-OS-000300-GPOS-00118, SRG-OS-000480-GPOS-00227
Fix Text
To disable the Wi-Fi network device, run the following command: /usr/bin/sudo /usr/sbin/networksetup -setnetworkserviceenabled "Wi-Fi" off
Check Content
If the system requires Wi-Fi to connect to an authorized network, this is not applicable. To check if the Wi-Fi network device is disabled, run the following command: /usr/bin/sudo /usr/sbin/networksetup -listallnetworkservices A disabled device will have an asterisk in front of its name. If the Wi-Fi device is missing this asterisk, this is a finding.
The macOS system must be configured with Infrared [IR] support disabled.
Discussion
IR kernel support must be disabled to prevent users from controlling the system with IR devices. By default, if IR is enabled, the system will accept IR control from any remote device.
Fix Text
To disable IR, run the following command: /usr/bin/sudo /usr/bin/defaults write /Library/Preferences/com.apple.driver.AppleIRController DeviceEnabled -bool FALSE
Check Content
To check if IR support is disabled, run the following command: /usr/bin/sudo /usr/bin/defaults read /Library/Preferences/com.apple.driver.AppleIRController DeviceEnabled If the result is not "0", this is a finding.
The macOS system must be configured with automatic actions disabled for blank CDs.
Discussion
Applications should not be configured to launch automatically when a disk is inserted. This potentially circumvents anti-virus software and allows malicious users to craft disks that can exploit user applications. Disabling Automatic Actions for blank CDs mitigates this risk.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
If an approved HBSS DCM/DLP solution is installed, this is not applicable. To check if the system has the correct setting for blank CDs in the configuration profile, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 2 'com.apple.digihub.blank.cd.appeared' If this is not defined or "action" is not set to "1", this is a finding.
The macOS system must be configured with automatic actions disabled for blank DVDs.
Discussion
Applications should not be configured to launch automatically when a disk is inserted. This potentially circumvents anti-virus software and allows malicious users to craft disks that can exploit user applications. Disabling Automatic Actions for blank DVDs mitigates this risk.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
If an approved HBSS DCM/DLP solution is installed, this is not applicable. To check if the system has the correct setting for blank DVDs in the configuration profile, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 2 'com.apple.digihub.blank.dvd.appeared' If this is not defined or "action" is not set to "1", this is a finding.
The macOS system must be configured with automatic actions disabled for music CDs.
Discussion
Applications should not be configured to launch automatically when a disk is inserted. This potentially circumvents anti-virus software and allows malicious users to craft disks that can exploit user applications. Disabling Automatic Actions for music CDs mitigates this risk.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
If an approved HBSS DCM/DLP solution is installed, this is not applicable. To check if the system has the correct setting for music CDs in the configuration profile, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 2 'com.apple.digihub.cd.music.appeared' If this is not defined or "action" is not set to "1", this is a finding.
The macOS system must be configured with automatic actions disabled for picture CDs.
Discussion
Applications should not be configured to launch automatically when a disk is inserted. This potentially circumvents anti-virus software and allows malicious users to craft disks that can exploit user applications. Disabling Automatic Actions for picture CDs mitigates this risk.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
If an approved HBSS DCM/DLP solution is installed, this is not applicable. To check if the system has the correct setting for picture CDs in the configuration profile, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 2 'com.apple.digihub.cd.picture.appeared' If this is not defined or "action" is not set to "1", this is a finding.
The macOS system must be configured with automatic actions disabled for video DVDs.
Discussion
Applications should not be configured to launch automatically when a disk is inserted. This potentially circumvents anti-virus software and allows malicious users to craft disks that can exploit user applications. Disabling Automatic Actions for video DVDs mitigates this risk.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
If an approved HBSS DCM/DLP solution is installed, this is not applicable. To check if the system has the correct setting for video DVDs in the configuration profile, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 2 'com.apple.digihub.dvd.video.appeared' If this is not defined or "action" is not set to "1", this is a finding.
The macOS system must automatically remove or disable temporary user accounts after 72 hours.
Discussion
If temporary user accounts remain active when no longer needed or for an excessive period, these accounts may be targeted by attackers to gain unauthorized access. To mitigate this risk, automated termination of all temporary accounts must be set upon account creation. Temporary accounts are established as part of normal account activation procedures when there is a need for short-term accounts without the demand for immediacy in account activation. If temporary accounts are used, the operating system must be configured to automatically terminate these types of accounts after a DoD-defined time period of 72 hours. To address access requirements, many operating systems may be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.
Fix Text
This setting may be enforced using a configuration profile or by a directory service. To set the password policy without a configuration profile, run the following command to save a copy of the current policy file, substituting the correct user name in place of "username": /usr/bin/sudo /usr/bin/pwpolicy -u username getaccountpolicies | tail -n +2 > pwpolicy.plist Open the resulting password policy file in a text editor. If other policy settings are present, and the line "<key>policyCategoryAuthentication</key>" already exists, insert the following text after the <array> tag that immediately follows it: <dict> <key>policyContent</key> <string>policyAttributeCurrentTime < policyAttributeCreationTime + 259299</string> <key>policyIdentifier</key> <string>Disable Temporary Account</string> </dict> At a minimum, edit the file to ensure that it contains the following text: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>policyCategoryAuthentication</key> <array> <dict> <key>policyContent</key> <string>policyAttributeCurrentTime < policyAttributeCreationTime + 259299</string> <key>policyIdentifier</key> <string>Disable Temporary Account</string> </dict> </array> </dict> </plist> After saving the file and exiting to the command prompt, run the following command to load the new policy file, substituting the correct user name in place of "username": /usr/bin/sudo /usr/bin/pwpolicy -u username setaccountpolicies pwpolicy.plist
Check Content
Verify if a password policy is enforced by a directory service by asking the System Administrator (SA) or Information System Security Officer (ISSO). If no policy is enforced by a directory service, a password policy can be set with the "pwpolicy" utility. The variable names may vary depending on how the policy was set. To check if the password policy is configured to disable a temporary account after 72 hours, run the following command to output the password policy to the screen, substituting the correct user name in place of username: /usr/bin/sudo /usr/bin/pwpolicy -u username getaccountpolicies | tail -n +2 If there is no output, and password policy is not controlled by a directory service, this is a finding. Otherwise, look for the line "<key>policyCategoryAuthentication</key>". In the array that follows, there should be a <dict> section that contains a check <string> that allows users to log in if "policyAttributeCurrentTime" is less than the result of adding "policyAttributeCreationTime" to 72 hours (259299 seconds). The check might use a variable defined in its "policyParameters" section. If the check does not exist or if the check adds too great an amount of time to "policyAttributeCreationTime", this is a finding.
The macOS system must automatically remove or disable emergency accounts after the crisis is resolved or within 72 hours.
Discussion
Emergency administrator accounts are privileged accounts established in response to crisis situations where the need for rapid account activation is required. Therefore, emergency account activation may bypass normal account authorization processes. If these accounts are automatically disabled, system maintenance during emergencies may not be possible, thus adversely affecting system availability. Emergency administrator accounts are different from infrequently used accounts (i.e., local logon accounts used by system administrators when network or normal logon/access is not available). Infrequently used accounts also remain available and are not subject to automatic termination dates. However, an emergency administrator account is normally a different account created for use by vendors or system maintainers. To address access requirements, many operating systems can be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.
Fix Text
To remove all "pwpolicy" settings for an emergency account, run the following command, replacing "username" with the correct value: /usr/bin/sudo /usr/bin/pwpolicy -u username clearaccountpolicies Otherwise, to change the password policy for an emergency account and only remove some policy sections, run the following command to save a copy of the current policy file for the specified username: /usr/bin/sudo /usr/bin/pwpolicy -u username getaccountpolicies | tail -n +2 > pwpolicy.plist Open the resulting password policy file in a text editor and remove any policyContent sections that would restrict the ability to log in after a certain date or amount of time. To remove the section cleanly, remove the entire text that begins with <dict>, contains the like <key>policyContent<'/key>, and ends with </dict>. After saving the file and exiting to the command prompt, run the following command to load the new policy file: /usr/bin/sudo /usr/bin/pwpolicy -u username setaccountpolicies pwpolicy.plist
Check Content
If an emergency account has been created on the system, check the expiration settings of a local account using the following command, replacing "username" with the correct value: /usr/bin/sudo /usr/bin/pwpolicy -u username getaccountpolicies | tail -n +2 If there is output, verify that the account policies do not restrict the ability to log in after a certain date or amount of time. If they do, this is a finding.
The macOS system must generate audit records for all account creations, modifications, disabling, and termination events; privileged activities or other system-level access; all kernel module load, unload, and restart actions; all program initiations; and organizationally defined events for all non-local maintenance and diagnostic sessions.
Discussion
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000327-GPOS-00127, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000476-GPOS-00221, SRG-OS-000477-GPOS-00222
Fix Text
To ensure the appropriate flags are enabled for auditing, run the following command: /usr/bin/sudo /usr/bin/sed -i.bak '/^flags/ s/$/,ad/' /etc/security/audit_control; /usr/bin/sudo /usr/sbin/audit -s A text editor may also be used to implement the required updates to the "/etc/security/audit_control" file.
Check Content
To view the currently configured flags for the audit daemon, run the following command: /usr/bin/sudo /usr/bin/grep ^flags /etc/security/audit_control Administrative and Privileged access, including administrative use of the command line tools "kextload" and "kextunload" and changes to configuration settings are logged by way of the "ad" flag. If "ad" is not listed in the result of the check, this is a finding.
The macOS system must be configured to disable SMB File Sharing unless it is required.
Discussion
File Sharing is usually non-essential and must be disabled if not required. Enabling any service increases the attack surface for an intruder. By disabling unnecessary services, the attack surface is minimized.
Fix Text
To disable the SMB File Sharing service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.smbd The system may need to be restarted for the update to take effect.
Check Content
If SMB File Sharing is required, this is not applicable. To check if the SMB File Sharing service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.smbd If the results do not show the following, this is a finding: "com.apple.smbd" => true
The macOS system must be configured to disable Apple File (AFP) Sharing.
Discussion
File Sharing is non-essential and must be disabled. Enabling any service increases the attack surface for an intruder. By disabling unnecessary services, the attack surface is minimized.
Fix Text
To disable the Apple File (AFP) Sharing service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.AppleFileServer The system may need to be restarted for the update to take effect.
Check Content
To check if the Apple File (AFP) Sharing service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.AppleFileServer If the results do not show the following, this is a finding: "com.apple.AppleFileServer" => true
The macOS system must be configured to disable the Network File System (NFS) daemon unless it is required.
Discussion
If the system does not require access to NFS file shares or is not acting as an NFS server, support for NFS is non-essential and NFS services must be disabled. NFS is a network file system protocol supported by UNIX-like operating systems. Enabling any service increases the attack surface for an intruder. By disabling unnecessary services, the attack surface is minimized.
Fix Text
To disable the NFS daemon, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.nfsd The system may need to be restarted for the update to take effect.
Check Content
If the NFS daemon is required, this is not applicable. To check if the NFS daemon is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.nfsd If the results do not show the following, this is a finding: "com.apple.nfsd" => true
The macOS system must be configured to disable the Network File System (NFS) lock daemon unless it is required.
Discussion
If the system does not require access to NFS file shares or is not acting as an NFS server, support for NFS is non-essential and NFS services must be disabled. NFS is a network file system protocol supported by UNIX-like operating systems. Enabling any service increases the attack surface for an intruder. By disabling unnecessary services, the attack surface is minimized.
Fix Text
To disable the NFS lock daemon, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.lockd The system may need to be restarted for the update to take effect.
Check Content
If the NFS lock daemon is required, this is not applicable. To check if the NFS lock daemon is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.lockd If the results do not show the following, this is a finding: "com.apple.lockd" => true
The macOS system must be configured to disable the Network File System (NFS) stat daemon unless it is required.
Discussion
If the system does not require access to NFS file shares or is not acting as an NFS server, support for NFS is non-essential and NFS services must be disabled. NFS is a network file system protocol supported by UNIX-like operating systems. Enabling any service increases the attack surface for an intruder. By disabling unnecessary services, the attack surface is minimized.
Fix Text
To disable the NFS stat daemon, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.statd.notify The system may need to be restarted for the update to take effect.
Check Content
If the NFS stat daemon is required, this is not applicable. To check if the NFS stat daemon is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.statd.notify If the results do not show the following, this is a finding: "com.apple.statd.notify" => true
The macOS system firewall must be configured with a default-deny policy.
Discussion
An approved firewall must be installed and enabled to work in concert with the macOS Application Firewall. When configured correctly, firewalls protect computers from network attacks by blocking or limiting access to open network ports.
Fix Text
Install an approved HBSS or firewall solution onto the system and configure it with a "default-deny" policy.
Check Content
Ask the System Administrator (SA) or Information System Security Officer (ISSO) if an approved firewall is loaded on the system. The recommended system is the McAfee HBSS. If no firewall is installed on the system, this is a finding. If a firewall is installed and it is not configured with a "default-deny" policy, this is a finding.
The macOS system must display the Standard Mandatory DoD Notice and Consent Banner before granting access to the operating system.
Discussion
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. The banner must be formatted in accordance with DTM-08-060.
Fix Text
Create a text file containing the required DoD text. Name the file "banner" and place it in "/etc/".
Check Content
Verify the operating system displays the Standard Mandatory DoD Notice and Consent Banner before granting access to the operating system. Check to see if the operating system has the correct text listed in the "/etc/banner" file with the following command: # more /etc/banner The command should return the following text: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." If the operating system does not display a graphical logon banner or the banner does not match the Standard Mandatory DoD Notice and Consent Banner, this is a finding. If the text in the "/etc/banner" file does not match the Standard Mandatory DoD Notice and Consent Banner, this is a finding.
The macOS system must display the Standard Mandatory DoD Notice and Consent Banner before granting access to the system via SSH.
Discussion
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. The banner must be formatted in accordance with DTM-08-060. Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007
Fix Text
For systems that allow remote access through SSH, modify the "/etc/ssh/sshd_config" file to add or update the following line: Banner /etc/banner
Check Content
For systems that allow remote access through SSH, run the following command to verify that "/etc/banner" is displayed before granting access: # /usr/bin/grep Banner /etc/ssh/sshd_config If the sshd Banner configuration option does not point to "/etc/banner", this is a finding.
The macOS system must be configured so that any connection to the system must display the Standard Mandatory DoD Notice and Consent Banner before granting access to the system.
Discussion
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. The banner must be formatted in accordance with DTM-08-060. Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007, SRG-OS-000228-GPOS-00088
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Create an RTF file containing the required text. Name the file "PolicyBanner.rtf" or "PolicyBanner.rtfd" and place it in "/Library/Security/".
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The policy banner will show if a "PolicyBanner.rtf" or "PolicyBanner.rtfd" exists in the "/Library/Security" folder. Run this command to show the contents of that folder: /bin/ls -l /Library/Security/PolicyBanner.rtf* If neither "PolicyBanner.rtf" nor "PolicyBanner.rtfd" exists, this is a finding. The banner text of the document MUST read: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." If the text is not worded exactly this way, this is a finding.
The macOS system must generate audit records for DoD-defined events such as successful/unsuccessful logon attempts, successful/unsuccessful direct access attempts, starting and ending time for user access, and concurrent logons to the same account from different sources.
Discussion
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000470-GPOS-00214, SRG-OS-000472-GPOS-00217, SRG-OS-000473-GPOS-00218, SRG-OS-000475-GPOS-00220
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To ensure the appropriate flags are enabled for auditing, run the following command: /usr/bin/sudo /usr/bin/sed -i.bak '/^flags/ s/$/,aa/' /etc/security/audit_control; /usr/bin/sudo /usr/sbin/audit -s A text editor may also be used to implement the required updates to the "/etc/security/audit_control" file.
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To view the currently configured flags for the audit daemon, run the following command: /usr/bin/sudo /usr/bin/grep ^flags /etc/security/audit_control Logon events are logged by way of the "aa" flag. If "aa" is not listed in the result of the check, this is a finding.
The macOS system must initiate session audits at system startup, using internal clocks with time stamps for audit records that meet a minimum granularity of one second and can be mapped to Coordinated Universal Time (UTC) or Greenwich Mean Time (GMT), in order to generate audit records containing information to establish what type of events occurred, the identity of any individual or process associated with the event, including individual identities of group account users, establish where the events occurred, source of the event, and outcome of the events including all account enabling actions, full-text recording of privileged commands, and information about the use of encryption for access wireless access to and from the system.
Discussion
Without establishing what type of events occurred, when they occurred, and by whom it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content that may be necessary to satisfy this requirement includes, for example, time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. Associating event types with detected events in the operating system audit logs provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured operating system. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00020, SRG-OS-000042-GPOS-00021, SRG-OS-000055-GPOS-00026, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000255-GPOS-00096, SRG-OS-000299-GPOS-00117, SRG-OS-000303-GPOS-00120, SRG-OS-000358-GPOS-00145, SRG-OS-000359-GPOS-00146
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To enable the audit service, run the following command: /usr/bin/sudo /bin/launchctl load -w /System/Library/LaunchDaemons/com.apple.auditd.plist
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To check if the audit service is running, use the following command: /usr/bin/sudo /bin/launchctl list | /usr/bin/grep com.apple.auditd If nothing is returned, the audit service is not running, and this is a finding.
The macOS system must enable System Integrity Protection.
Discussion
The System Integrity Protection is vital to prevent unauthorized and unintended information transfer via shared system resources, protect audit tools from unauthorized access, modification, and deletion, limit privileges to change software resident within software libraries, limit the ability of non-privileged users to grant other users direct access to the contents of their home directories/folders. SIP also ensures the presence of an audit record generation capability for DoD-defined auditable events for all operating system components, supports on-demand and after-the-fact reporting requirements, does not alter original content or time ordering of audit records. Satisfies: SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000062-GPOS-00031, SRG-OS-000122-GPOS-00063, SRG-OS-000138-GPOS-00069, SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000259-GPOS-00100, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00230
Fix Text
To reenable "System Integrity Protection", boot the affected system into "Recovery" mode, launch "Terminal" from the "Utilities" menu, and run the following command: /usr/bin/csrutil enable
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System Integrity Protection is a security feature, enabled by default, that protects certain system processes and files from being modified or tampered with. Check the current status of "System Integrity Protection" with the following command: /usr/bin/csrutil status If the result does not show the following, this is a finding. System Integrity Protection status: enabled
The macOS system must allocate audit record storage capacity to store at least one weeks worth of audit records when audit records are not immediately sent to a central audit record storage facility.
Discussion
The audit service must be configured to require that records are kept for seven days or longer before deletion when there is no central audit record storage facility. When "expire-after" is set to "7d", the audit service will not delete audit logs until the log data is at least seven days old.
Fix Text
Edit the "/etc/security/audit_control" file and change the value for "expire-after" to the amount of time audit logs should be kept for the system. Use the following command to set the "expire-after" value to "7d": /usr/bin/sudo /usr/bin/sed -i.bak 's/.*expire-after.*/expire-after:7d/' /etc/security/audit_control; /usr/bin/sudo /usr/sbin/audit -s A text editor may also be used to implement the required updates to the "/etc/security/audit_control" file.
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The check displays the amount of time the audit system is configured to retain audit log files. The audit system will not delete logs until the specified condition has been met. To view the current setting, run the following command: /usr/bin/sudo /usr/bin/grep ^expire-after /etc/security/audit_control If this returns no results, or does not contain "7d" or a larger value, this is a finding.
The macOS system must provide an immediate warning to the System Administrator (SA) and Information System Security Officer (ISSO) (at a minimum) when allocated audit record storage volume reaches 75 percent of repository maximum audit record storage capacity.
Discussion
The audit service must be configured to require a minimum percentage of free disk space in order to run. This ensures that audit will notify the administrator that action is required to free up more disk space for audit logs. When "minfree" is set to 25 percent, security personnel are notified immediately when the storage volume is 75 percent full and are able to plan for audit record storage capacity expansion.
Fix Text
Edit the "/etc/security/audit_control" file and change the value for "minfree" to "25" using the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/.*minfree.*/minfree:25/' /etc/security/audit_control; /usr/bin/sudo /usr/sbin/audit -s A text editor may also be used to implement the required updates to the "/etc/security/audit_control file".
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The check displays the "% free" to leave available for the system. The audit system will not write logs if the volume has less than this percentage of free disk space. To view the current setting, run the following command: /usr/bin/sudo /usr/bin/grep ^minfree /etc/security/audit_control If this returns no results, or does not contain "25", this is a finding.
The macOS system must provide an immediate real-time alert to the System Administrator (SA) and Information System Security Officer (ISSO), at a minimum, of all audit failure events requiring real-time alerts.
Discussion
The audit service should be configured to immediately print messages to the console or email administrator users when an auditing failure occurs. It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without a real-time alert, security personnel may be unaware of an impending failure of the audit capability and system operation may be adversely affected.
Fix Text
To make "auditd" log errors to standard error as well as "syslogd", run the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/logger -p/logger -s -p/' /etc/security/audit_warn; /usr/bin/sudo /usr/sbin/audit -s
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By default, "auditd" only logs errors to "syslog". To see if audit has been configured to print error messages to the console, run the following command: /usr/bin/sudo /usr/bin/grep logger /etc/security/audit_warn If the argument "-s" is missing, or if "audit_warn" has not been otherwise modified to print errors to the console or send email alerts to the SA and ISSO, this is a finding.
The macOS system must, for networked systems, compare internal information system clocks at least every 24 hours with a server that is synchronized to one of the redundant United States Naval Observatory (USNO) time servers or a time server designated for the appropriate DoD network (NIPRNet/SIPRNet) and/or the Global Positioning System (GPS).
Discussion
Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside of the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints). Satisfies: SRG-OS-000355-GPOS-00143, SRG-OS-000356-GPOS-00144
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To enable the NTP service, run the following command: /usr/bin/sudo /bin/launchctl load -w /System/Library/LaunchDaemons/org.ntp.ntpd.plist To configure one or more time servers for use, edit "/etc/ntp.conf" and enter each hostname or IP address on a separate line, prefixing each one with the keyword "server".
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The Network Time Protocol (NTP) service must be enabled on all networked systems. To check if the service is running, use the following command: /usr/bin/sudo /bin/launchctl list | grep org.ntp.ntpd If nothing is returned, this is a finding. To verify that an authorized NTP server is configured, run the following command or examine "/etc/ntp.conf": /usr/bin/sudo /usr/bin/grep ^server /etc/ntp.conf Only approved time servers should be configured for use. If no server is configured, or if an unapproved time server is in use, this is a finding.
The macOS system must be configured with audit log files owned by root.
Discussion
The audit service must be configured to create log files with the correct ownership to prevent regular users from reading audit logs. Audit logs contain sensitive data about the system and users. If log files are set to only be readable and writable by root or administrative users with sudo, the risk is mitigated.
Fix Text
For any log file that returns an incorrect owner, run the following command: /usr/bin/sudo chown root [audit log file] [audit log file] is the full path to the log file in question.
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To check the ownership of the audit log files, run the following command: /usr/bin/sudo ls -le $(/usr/bin/sudo /usr/bin/grep '^dir' /etc/security/audit_control | awk -F: '{print $2}') | grep -v current The results should show the owner (third column) to be "root". If they do not, this is a finding.
The macOS system must be configured with audit log folders owned by root.
Discussion
The audit service must be configured to create log files with the correct ownership to prevent regular users from reading audit logs. Audit logs contain sensitive data about the system and about users. If log files are set to be readable and writable only by root or administrative users with sudo, the risk is mitigated.
Fix Text
For any log folder that has an incorrect owner, run the following command: /usr/bin/sudo chown root [audit log folder]
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To check the ownership of the audit log folder, run the following command: /usr/bin/sudo ls -lde $(/usr/bin/sudo /usr/bin/grep '^dir' /etc/security/audit_control | awk -F: '{print $2}') The results should show the owner (third column) to be "root". If it does not, this is a finding.
The macOS system must be configured with audit log files group-owned by wheel.
Discussion
The audit service must be configured to create log files with the correct group ownership to prevent regular users from reading audit logs. Audit logs contain sensitive data about the system and users. If log files are set to be readable and writable only by root or administrative users with sudo, the risk is mitigated.
Fix Text
For any log file that returns an incorrect group owner, run the following command: /usr/bin/sudo chgrp wheel [audit log file] [audit log file] is the full path to the log file in question.
Check Content
To check the group ownership of the audit log files, run the following command: /usr/bin/sudo ls -le $(/usr/bin/sudo /usr/bin/grep '^dir' /etc/security/audit_control | awk -F: '{print $2}') | /usr/bin/grep -v current The results should show the group owner (fourth column) to be "wheel". If they do not, this is a finding.
The macOS system must be configured with audit log folders group-owned by wheel.
Discussion
The audit service must be configured to create log files with the correct group ownership to prevent regular users from reading audit logs. Audit logs contain sensitive data about the system and about users. If log files are set to be readable and writable only by root or administrative users with sudo, the risk is mitigated.
Fix Text
For any log folder that has an incorrect group, run the following command: /usr/bin/sudo chgrp wheel [audit log folder]
Check Content
To check the group ownership of the audit log folder, run the following command: /usr/bin/sudo ls -lde $(/usr/bin/sudo /usr/bin/grep '^dir' /etc/security/audit_control | awk -F: '{print $2}') The results should show the group (fourth column) to be "wheel". If they do not, this is a finding.
The macOS system must be configured with audit log files set to mode 440 or less permissive.
Discussion
The audit service must be configured to create log files with the correct permissions to prevent regular users from reading audit logs. Audit logs contain sensitive data about the system and about users. If log files are set to be readable and writable only by root or administrative users with sudo, the risk is mitigated.
Fix Text
For any log file that returns an incorrect permission value, run the following command: /usr/bin/sudo chmod 440 [audit log file] [audit log file] is the full path to the log file in question.
Check Content
To check the permissions of the audit log files, run the following command: /usr/bin/sudo ls -le $(/usr/bin/sudo /usr/bin/grep '^dir' /etc/security/audit_control | awk -F: '{print $2}') | /usr/bin/grep -v current The results should show the permissions (first column) to be "440" or less permissive. If they do not, this is a finding.
The macOS system must be configured with audit log folders set to mode 700 or less permissive.
Discussion
The audit service must be configured to create log folders with the correct permissions to prevent regular users from reading audit logs. Audit logs contain sensitive data about the system and users. If log folders are set to be readable and writable only by root or administrative users with sudo, the risk is mitigated. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029
Fix Text
For any log folder that returns an incorrect permission value, run the following command: /usr/bin/sudo chmod 700 [audit log folder]
Check Content
To check the permissions of the audit log folder, run the following command: /usr/bin/sudo ls -lde $(/usr/bin/sudo /usr/bin/grep '^dir' /etc/security/audit_control | awk -F: '{print $2}') The results should show the permissions (first column) to be "700" or less permissive. If they do not, this is a finding.
The macOS system must be configured so that log files must not contain access control lists (ACLs).
Discussion
The audit service must be configured to create log files with the correct permissions to prevent regular users from reading audit logs. Audit logs contain sensitive data about the system and users. If log files are set to be readable and writable only by root or administrative users with sudo, the risk is mitigated.
Fix Text
For any log file that contains ACLs, run the following command: /usr/bin/sudo chmod -N [audit log file]
Check Content
To check if a log file contains ACLs, run the following commands: /usr/bin/sudo ls -le $(/usr/bin/sudo /usr/bin/grep '^dir' /etc/security/audit_control | awk -F: '{print $2}') | /usr/bin/grep -v current In the output from the above commands, ACLs will be listed under any file that may contain them (e.g., "0: group:admin allow list,readattr,reaadextattr,readsecurity"). If any such line exists, this is a finding.
The macOS system must be configured so that log folders must not contain access control lists (ACLs).
Discussion
The audit service must be configured to create log folders with the correct permissions to prevent regular users from reading audit logs. Audit logs contain sensitive data about the system and users. If log folders are set to be readable and writable only by root or administrative users with sudo, the risk is mitigated.
Fix Text
For any log folder that contains ACLs, run the following command: /usr/bin/sudo chmod -N [audit log folder]
Check Content
To check if a log folder contains ACLs, run the following commands: /usr/bin/sudo ls -lde $(/usr/bin/sudo /usr/bin/grep '^dir' /etc/security/audit_control | awk -F: '{print $2}') In the output from the above commands, ACLs will be listed under any folder that may contain them (e.g., "0: group:admin allow list,readattr,reaadextattr,readsecurity"). If any such line exists, this is a finding.
The macOS system must have the security assessment policy subsystem enabled.
Discussion
Any changes to the hardware, software, and/or firmware components of the information system and/or application can potentially have significant effects on the overall security of the system. Accordingly, software defined by the organization as critical must be signed with a certificate that is recognized and approved by the organization.
Fix Text
To enable the Security assessment policy subsystem, run the following command: /usr/bin/sudo /usr/sbin/spctl --master-enable
Check Content
To check the status of the Security assessment policy subsystem, run the following command: /usr/bin/sudo /usr/sbin/spctl --status | /usr/bin/grep enabled If nothing is returned, this is a finding.
The macOS system must be configured to disable the application FaceTime.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The application FaceTime establishes connections to Apple's iCloud, despite using security controls to disable iCloud access. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if there is a configuration policy defined for "Application Restrictions", run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 5 familyControlsEnabled | grep "FaceTime" If the result does not contain "/Applications/FaceTime.app", this is a finding.
The macOS system must be configured to disable the application Messages.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The application Messages establishes connections to Apple's iCloud, despite using security controls to disable iCloud access. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if there is a configuration policy defined for "Application Restrictions", run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 5 familyControlsEnabled | grep "Messages.app" If the result does not contain "/Applications/Messages.app", this is a finding.
The macOS system must be configured to disable the iCloud Calendar services.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The application Calendar establishes connections to Apple's iCloud, despite using security controls to disable iCloud access. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if iCloud Calendar is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudCalendar If the result is not “allowCloudCalendar = 0”, this is a finding.
The macOS system must be configured to disable the iCloud Reminders services.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The application Reminders establishes connections to Apple's iCloud, despite using security controls to disable iCloud access. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if iCloud Reminders is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudReminders If the result is not “allowCloudReminders = 0”, this is a finding.
The macOS system must be configured to disable iCloud Address Book services.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The application Address Book establishes connections to Apple's iCloud, despite using security controls to disable iCloud access. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if iCloud Address Book is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudAddressBook If the result is not “allowCloudAddressBook = 0”, this is a finding.
The macOS system must be configured to disable the iCloud Mail services.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The application Mail establishes connections to Apple's iCloud, despite using security controls to disable iCloud access. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if iCloud Mail is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudMail If the result is not “allowCloudMail = 0”, this is a finding.
The macOS system must be configured to disable the iCloud Notes services.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The application Notes establishes connections to Apple's iCloud, despite using security controls to disable iCloud access. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if iCloud Notes is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudNotes If the result is not “allowCloudNotes = 0”, this is a finding.
The macOS system must be configured to disable the camera.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The system preference panel's iCloud and Internet Accounts must be disabled. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if the system has been configured to disable the camera, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCamera If the result is not “allowCamera = 0”, this is a finding.
The macOS system must be configured to disable the system preference pane for iCloud.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The system preference panes for iCloud and Internet Accounts must be disabled. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if the system has the correct setting in the configuration profile to disable access to the iCloud preference pane, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 5 DisabledPreferencePanes | grep icloud If the return is not “com.apple.preferences.icloud”, this is a finding.
The macOS system must be configured to disable the system preference pane for Internet Accounts.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The system preference panes for iCloud and Internet Accounts must be disabled. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if "Internet Accounts" has been disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 5 DisabledPreferencePanes | grep internetaccounts If the return is not "com.apple.preferences.internetaccounts", this is a finding.
The macOS system must be configured to disable the system preference pane for Siri.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The system preference panes for Siri and dictation must be disabled. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if "Siri" has been disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 5 DisabledPreferencePanes | grep speech If the return is not “com.apple.preference.speech”, this is a finding.
The macOS system must be configured to disable Siri and dictation.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The system preference panes for Siri and dictation must be disabled. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if Siri and dictation has been disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -E '(allowAssistant | IronwoodAllowed)’ If the return is null or not: “IronwoodAllowed = 0 allowAssistant = 0”, this is a finding.
The macOS system must be configured to disable sending diagnostic and usage data to Apple.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. Sending diagnostic and usage data to Apple must be disabled.
Fix Text
This setting is enforced using the "Security and Privacy Policy" configuration profile. The setting "Send diagnostic & usage data to Apple" is found in System Preferences >> Security & Privacy >> Privacy >> Diagnostics & Usage. Uncheck the box that says "Send diagnostic & usage data to Apple." To apply the setting from the command line, run the following commands: /usr/bin/defaults read "/Library/Application Support/CrashReporter/DiagnosticMessagesHistory.plist" AutoSubmit /usr/bin/sudo /usr/bin/defaults write "/Library/Application Support/CrashReporter/DiagnosticMessagesHistory.plist" AutoSubmit -bool false /usr/bin/sudo /bin/chmod 644 /Library/Application\ Support/CrashReporter/DiagnosticMessagesHistory.plist /usr/bin/sudo /usr/bin/chgrp admin /Library/Application\ Support/CrashReporter/DiagnosticMessagesHistory.plist
Check Content
Sending diagnostic and usage data to Apple must be disabled. To check if a configuration profile is configured to enforce this setting, run the following command: /usr/bin/sudo /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowDiagnosticSubmission If "allowDiagnosticSubmission" is not set to "0", this is a finding. Alternately, the setting is found in System Preferences >> Security & Privacy >> Privacy >> Diagnostics & Usage. If the box that says "Send diagnostic & usage data to Apple" is checked, this is a finding.
The macOS system must be configured to disable the iCloud Find My Mac service.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality-of-life issues. Find My Mac must be disabled. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if Find My Mac is disabled, use the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudFMM If the return is null or not “allowCloudFMM = 0”, this is a finding.
The macOS system must be configured to disable Location Services.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality-of-life issues. Location Services must be disabled.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile. The setting "Enable Location Services" can be found in System Preferences >> Security & Privacy >> Privacy >> Location Services. Uncheck the box that says "Enable Location Services". It can also be set with the following command: /usr/bin/sudo /usr/bin/defaults write /private/var/db/locationd/Library/Preferences/ByHost/com.apple.locationd.`/usr/sbin/system_profiler SPHardwareDataType | /usr/bin/grep "Hardware UUID" | /usr/bin/cut -c22-57` LocationServicesEnabled -bool false
Check Content
Location Services must be disabled. To check if a configuration profile is configured to enforce this setting, run the following command: /usr/bin/sudo /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep DisableLocationServices If the return is null or not “DisableLocationServices = 1”, this is a finding. The setting is found in System Preferences >> Security & Privacy >> Privacy >> Location Services. If the box that says "Enable Location Services" is checked, this is a finding. To check if the setting was applied on the command line, run the following command: /usr/bin/sudo /usr/bin/defaults read /private/var/db/locationd/Library/Preferences/ByHost/com.apple.locationd.`/usr/sbin/system_profiler SPHardwareDataType | /usr/bin/grep "Hardware UUID" | /usr/bin/cut -c22-57` LocationServicesEnabled If the result is "1" this is a finding.
The macOS system must be configured to disable Bonjour multicast advertising.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. Bonjour multicast advertising must be disabled on the system.
Fix Text
To configure Bonjour to disable multicast advertising, run the following command: /usr/bin/sudo /usr/bin/defaults write /Library/Preferences/com.apple.mDNSResponder.plist NoMulticastAdvertisements -bool true The system will need to be restarted for the update to take effect.
Check Content
To check if Bonjour multicast advertising has been disabled, run the following command: /usr/bin/sudo /usr/bin/defaults read /Library/Preferences/com.apple.mDNSResponder | /usr/bin/grep NoMulticastAdvertisements If an error is returned, nothing is returned, or "NoMulticastAdvertisements" is not set to "1", this is a finding.
The macOS system must be configured to disable the UUCP service.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. The system must not have the UUCP service active.
Fix Text
To disable the UUCP service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.uucp The system may need to be restarted for the update to take effect.
Check Content
To check if the UUCP service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.uucp If the results do not show the following, this is a finding: "com.apple.uucp" => true
The macOS system must disable the Touch ID feature.
Discussion
The Touch ID feature permits users to add additional fingerprints to unlock the host. These fingerprints may be for the user or anyone else. Because unauthorized users may gain access to the system, the use of Touch ID must be limited.
Fix Text
This setting is enforced using the "Restrictions" configuration profile.
Check Content
To view the setting for Touch ID configuration, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowFingerprintForUnlock If the output is null, not "allowFingerprintForUnlock = 0" this is a finding.
The macOS system must obtain updates from a DoD-approved update server.
Discussion
Software update configuration. Point to DOD approved update server. Configure for automatic install of critical updates.
Fix Text
To remove the Apple software list from the system configuration run the following command: sudo defaults delete /Library/Preferences/com.apple.SoftwareUpdate.plist CatalogURL
Check Content
To check if the CatalogURL is configured, run the following command: defaults read /Library/Preferences/com.apple.SoftwareUpdate.plist CatalogURL 2017-11-30 22:21:41.805 defaults[1205:9595] The domain/default pair of (/Library/Preferences/com.apple.SoftwareUpdate.plist, CatalogURL) does not exist. If the output is not an error indicating the item "does not exist" or the output is not a DoD-approved update server, this is a finding. Note: Updates are required to be applied with a frequency determined by the site or Program Management Office (PMO).
The macOS system must not have a root account.
Discussion
To assure individual accountability and prevent unauthorized access, organizational users must be individually identified and authenticated.
Fix Text
Disable the root account with the following command: /usr/sbin/dsenableroot -d
Check Content
To check if the root account is disabled, run the following command: defaults read /var/db/dslocal/nodes/Default/users/root.plist passwd ( "*" ) The output should be a single asterisk in quotes, as seen above. If the output is as follow, this is a finding: ( "********" )
The macOS system must not have a guest account.
Discussion
Only authorized individuals should be allowed to obtain access to operating system components. Permitting access via a guest account provides unauthenticated access to any person.
Fix Text
Remove the guest user with the following command: sudo dscl . delete /Users/Guest "This can also be managed with "Login Window Policy" configuration profile.
Check Content
To check if the guest user exists, run the following command: dscl . list /Users | grep -i Guest To verify that Guest user cannot unlock volume, run the following command: fdesetup list To check if the system is configured to prohibit user installation of software, first check to ensure the Parental Controls are enabled with the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -E '(DisableGuestAccount | EnableGuestAccount)’ If the result is null or not: DisableGuestAccount = 1; EnableGuestAccount = 0; This is a finding.
The macOS system must unload tftpd.
Discussion
The "tftp" service must be disabled as it sends all data in a clear-text form that can be easily intercepted and read. The data needs to be protected at all times during transmission, and encryption is the standard method for protecting data in transit. If the data is not encrypted during transmission, it can be plainly read (i.e., clear text) and easily compromised. Disabling ftp is one way to mitigate this risk. Administrators should be instructed to use an alternate service for data transmission that uses encryption, such as SFTP. Additionally, the "tftp" service uses UDP, which is not secure.
Fix Text
To disable the "tfpd" service, run the following command: sudo launchctl unload -w /System/Library/LaunchDaemons/tftp.plist
Check Content
To check if the "tfptd" service is disabled, run the following command: sudo launchctl print-disabled system | grep tftp If "com.apple.tftp" is not set to "true", this is a finding.
The macOS system must disable Siri pop-ups.
Discussion
Users (and any processes acting on behalf of users) need to be uniquely identified and authenticated for all accesses other than those accesses explicitly identified and documented by the organization, which outlines specific user actions that can be performed on the Ubuntu operating system without identification or authentication. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Login Window" configuration profile.
Check Content
To check if the "SkipSiriSetup" prompt is enabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep SkipSiriSetup If the output is null or "SkipSiriSetup" is not set to "1", this is a finding.
The macOS system must disable iCloud Back to My Mac feature.
Discussion
The Back to My Mac is an iCloud feature permitting users to connect to a Mac, AirPort Disk, or Time Capsule using another Mac or another Internet connected device. When connected users can transfer data and see a live version of the screen content. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions" configuration profile.
Check Content
To view the setting for the Back to My Mac configuration, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudBTMM If the output is null or not "allowCloudBTMM = 0" this is a finding.
The macOS system must disable iCloud Keychain synchronization.
Discussion
Requiring individuals to be authenticated with an individual authenticator prior to using a group authenticator allows for traceability of actions, as well as adding an additional level of protection of the actions that can be taken with group account knowledge. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions" configuration profile.
Check Content
To view the setting for the iCloud Keychain Synchronization configuration, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudKeychainSync If the output is null or not "allowCloudKeychainSync = 0" this is a finding.
The macOS system must disable iCloud document synchronization.
Discussion
Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions" configuration profile.
Check Content
To view the setting for the iCloud Document Synchronization configuration, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudDocumentSync If the output is null or not "allowCloudDocumentSync = 0" this is a finding.
The macOS system must disable iCloud bookmark synchronization.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions" configuration profile.
Check Content
To view the setting for the iCloud Bookmark Synchronization configuration, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudBookmarks If the output is null or not "allowCloudBookmarks = 0" this is a finding.
The macOS system must disable iCloud Photo Library.
Discussion
To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality-of-life issues. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions" configuration profile.
Check Content
To view the setting for the iCloud Photo Library configuration, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudPhotoLibrary If the output is null or not "allowCloudPhotoLibrary = 0" this is a finding.
The macOS system must disable iCloud Desktop And Documents.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Satisfies: SRG-OS-000095-GPOS-00049, SRG-OS-000370-GPOS-00155
Fix Text
This setting is enforced using the "Restrictions" configuration profile.
Check Content
To view the setting for the iCloud Desktop And Documents configuration, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudDesktopAndDocuments If the output is null or not "allowCloudDesktopAndDocuments = 0" this is a finding.
The macOS system must require individuals to be authenticated with an individual authenticator prior to using a group authenticator.
Discussion
Administrators must never log in directly as root. To assure individual accountability and prevent unauthorized access, logging in as root over a remote connection must be disabled. Administrators should only run commands as root after first authenticating with their individual user names and passwords.
Fix Text
To ensure that "PermitRootLogin" is disabled by sshd, run the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/^[\#]*PermitRootLogin.*/PermitRootLogin no/' /etc/ssh/sshd_config
Check Content
To check if SSH has root logins enabled, run the following command: /usr/bin/sudo /usr/bin/grep ^PermitRootLogin /etc/ssh/sshd_config If there is no result, or the result is set to "yes", this is a finding.
The macOS system must implement NSA-approved cryptography to protect classified information in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards.
Discussion
Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated. Satisfies: SRG-OS-000112-GPOS-00057, SRG-OS-000113-GPOS-00058, SRG-OS-000396-GPOS-00176
Fix Text
To ensure that "Protocol 2" is used by sshd, run the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/.*Protocol.*/Protocol 2/' /etc/ssh/sshd_config
Check Content
To check which protocol is configured for sshd, run the following: /usr/bin/sudo /usr/bin/grep ^Protocol /etc/ssh/sshd_config If there is no result or the result is not "Protocol 2", this is a finding.
The macOS system must enforce password complexity by requiring that at least one numeric character be used.
Discussion
Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.
Fix Text
This setting may be enforced using the "Passcode Policy" configuration profile or by a directory service. To set the password policy without a configuration profile, run the following command to save a copy of the current "pwpolicy" account policy file: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies | tail -n +2 > pwpolicy.plist Open the generated file in a text editor. If the file does not yet contain any policy settings, replace <dict/> with <dict></dict>; then insert the following text after the opening <dict> tag and before the closing </dict> tag. The same text can also be used if the line "<key>policyCategoryPasswordContent</key>" is not present. <key>policyCategoryPasswordContent</key> <array> <dict> <key>policyContent</key> <string>policyAttributePassword matches '(.*[0-9].*){1,}+'</string> <key>policyIdentifier</key> <string>com.apple.policy.legacy.requiresNumeric</string> <key>policyParameters</key> <dict> <key>minimumNumericCharacters</key> <integer>1</integer> </dict> </dict> </array> If the file does contain policy settings, and the line "<key>policyCategoryPasswordContent</key>" does exist, insert the following text after the opening <array> tag that comes right after it: <dict> <key>policyContent</key> <string>policyAttributePassword matches '(.*[0-9].*){1,}+'</string> <key>policyIdentifier</key> <string>com.apple.policy.legacy.requiresNumeric</string> <key>policyParameters</key> <dict> <key>minimumNumericCharacters</key> <integer>1</integer> </dict> </dict> After saving the file and exiting to the command prompt, run the following command to load the new policy file: /usr/bin/sudo /usr/bin/pwpolicy setaccountpolicies pwpolicy.plist Note: Updates to password restrictions must be thoroughly evaluated in a test environment. Mistakes in configuration may block password change and local user creation operations, as well as lock out all local users, including administrators.
Check Content
Password policy can be set with a configuration profile or the "pwpolicy" utility. If password policy is set with a configuration profile, run the following command to check if the system is configured to require that passwords contain at least one numeric character: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep requireAlphanumeric If the result is null or is not “requireAlphanumeric = 1”, this is a finding. If password policy is set with the "pwpolicy utility", run the following command instead: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies Look for the line "<key>policyCategoryPasswordContent</key>". If it does not exist, and password policy is not controlled by a directory service, this is a finding. Otherwise, in the array section that follows it, there should be a <dict> section that contains a check <string> that "matches" the variable "policyAttributePassword" to the regular expression "(.*[0-9].*){1,}+" or to a similar expression that will ensure the password contains a character in the range 0-9 one or more times. If this check allows users to create passwords without at least one numeric character, or if no such check exists, this is a finding.
The macOS system must enforce password complexity by requiring that at least one special character be used.
Discussion
Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity or strength is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor in determining how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Special characters are those characters that are not alphanumeric. Examples include: ~ ! @ # $ % ^ *.
Fix Text
This setting may be enforced using the "Passcode Policy" configuration profile or by a directory service.
Check Content
Password policy can be set with a configuration profile or the "pwpolicy" utility. If password policy is set with a configuration profile, run the following command to check if the system is configured to require that passwords contain at least one special character: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep minComplexChars If the return is null or not ” minComplexChars = 1”, this is a finding. Run the following command to check if the system is configured to require that passwords not contain repeated sequential characters or characters in increasing and decreasing sequential order: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowSimple If "allowSimple" is not set to "0" or is undefined, this is a finding.
The macOS system must enforce a minimum 15-character password length.
Discussion
The minimum password length must be set to 15 characters. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. The use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.
Fix Text
This setting is enforced using the "Passcode Policy" configuration profile. Note: Updates to password restrictions must be thoroughly evaluated in a test environment. Mistakes in configuration may block password change and local user creation operations, as well as lock out all local users, including administrators.
Check Content
To check the currently applied policies for passwords and accounts, use the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep minLength If the return is null or not “minLength = 15”, this is a finding.
The macOS system must not use telnet.
Discussion
The "telnet" service must be disabled as it sends all data in a clear-text form that can be easily intercepted and read. The data needs to be protected at all times during transmission, and encryption is the standard method for protecting data in transit. If the data is not encrypted during transmission, it can be plainly read (i.e., clear text) and easily compromised. Disabling telnet is one way to mitigate this risk. Administrators should be instructed to use an alternate service for remote access sessions, non-local maintenance sessions, and diagnostic communications that uses encryption, such as SSH. Satisfies: SRG-OS-000074-GPOS-00042, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174
Fix Text
To disable the "telnet" service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.telnetd The system may need to be restarted for the update to take effect.
Check Content
To check if the "telnet" service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.telnetd If the results do not show the following, this is a finding: "com.apple.telnetd" => true
The macOS system must not use unencrypted FTP.
Discussion
The "ftp" service must be disabled as it sends all data in a clear-text form that can be easily intercepted and read. The data needs to be protected at all times during transmission, and encryption is the standard method for protecting data in transit. If the data is not encrypted during transmission, it can be plainly read (i.e., clear text) and easily compromised. Disabling ftp is one way to mitigate this risk. Administrators should be instructed to use an alternate service for data transmission that uses encryption, such as SFTP.
Fix Text
To disable the "ftp" service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.ftpd The system may need to be restarted for the update to take effect.
Check Content
To check if the "ftp" service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.ftpd If the results do not show the following, this is a finding: "com.apple.ftpd" => true
The macOS system must allow only applications downloaded from the App Store to run.
Discussion
Gatekeeper settings must be configured correctly to only allow the system to run applications downloaded from the Mac App Store or applications signed with a valid Apple Developer ID code. Administrator users will still have the option to override these settings on a per-app basis. Gatekeeper is a security feature that ensures that applications must be digitally signed by an Apple-issued certificate in order to run. Digital signatures allow the macOS host to verify that the application has not been modified by a malicious third party.
Fix Text
This setting is enforced using the "Security and Privacy Policy" configuration profile.
Check Content
To verify only applications downloaded from the App Store are allowed to run, type the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -E '(EnableAssessment | AllowIdentifiedDevelopers)’ If the return is null, or is not: AllowIdentifiedDevelopers = 1; EnableAssessment = 1; This is a finding.
The macOS system must be configured so that end users cannot override Gatekeeper settings.
Discussion
Gatekeeper must be configured with a configuration profile to prevent regular users from overriding its setting. If regular users are allowed to disable Gatekeeper or set it to a less restrictive setting, malware could be introduced into the system. Gatekeeper is a security feature that ensures applications must be digitally signed by an Apple-issued certificate in order to run. Digital signatures allow the macOS host to verify the application has not been modified by a malicious third party.
Fix Text
This setting is enforced using the "Security and Privacy Policy" configuration profile.
Check Content
To verify the regular user cannot override Gatekeeper settings, type the following code: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep DisableOverride If "DisableOverride" is not set to "1", this is a finding.
The macOS system must be configured with the SSH daemon ClientAliveInterval option set to 900 or less.
Discussion
SSH should be configured to log users out after a 15-minute interval of inactivity and to wait only 30 seconds before timing out logon attempts. Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session or an incomplete logon attempt will also free up resources committed by the managed network element.
Fix Text
To ensure that "ClientAliveInterval" is set correctly, run the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/.*ClientAliveInterval.*/ClientAliveInterval 900/' /etc/ssh/sshd_config
Check Content
The SSH daemon "ClientAliveInterval" option must be set correctly. To check the idle timeout setting for SSH sessions, run the following: /usr/bin/sudo /usr/bin/grep ^ClientAliveInterval /etc/ssh/sshd_config If the setting is not "900" or less, this is a finding.
The macOS system must be configured with the SSH daemon ClientAliveCountMax option set to 0.
Discussion
SSH should be configured to log users out after a 15-minute interval of inactivity and to wait only 30 seconds before timing out logon attempts. Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session or an incomplete logon attempt will also free up resources committed by the managed network element.
Fix Text
To ensure that the SSH idle timeout occurs precisely when the "ClientAliveCountMax" is set, run the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/.*ClientAliveCountMax.*/ClientAliveCountMax 0/' /etc/ssh/sshd_config
Check Content
The SSH daemon "ClientAliveCountMax" option must be set correctly. To verify the SSH idle timeout will occur when the "ClientAliveCountMax" is set, run the following command: /usr/bin/sudo /usr/bin/grep ^ClientAliveCountMax /etc/ssh/sshd_config If the setting is not "ClientAliveCountMax 0", this is a finding.
The macOS system must be configured with the SSH daemon LoginGraceTime set to 30 or less.
Discussion
SSH should be configured to log users out after a 15-minute interval of inactivity and to wait only 30 seconds before timing out logon attempts. Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session or an incomplete logon attempt will also free up resources committed by the managed network element.
Fix Text
To ensure that "LoginGraceTime" is configured correctly, run the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/.*LoginGraceTime.*/LoginGraceTime 30/' /etc/ssh/sshd_config
Check Content
The SSH daemon "LoginGraceTime" must be set correctly. To check the amount of time that a user can log on through SSH, run the following command: /usr/bin/sudo /usr/bin/grep ^LoginGraceTime /etc/ssh/sshd_config If the value is not set to "30" or less, this is a finding.
The macOS system must issue or obtain public key certificates under an appropriate certificate policy from an approved service provider.
Discussion
DoD-approved certificates must be installed to the System Keychain so they will be available to all users. For user certificates, each organization obtains certificates from an approved, shared service provider, as required by OMB policy. For federal agencies operating a legacy public key infrastructure cross-certified with the Federal Bridge Certification Authority at medium assurance or higher, this Certification Authority will suffice. This control focuses on certificates with a visibility external to the information system and does not include certificates related to internal system operations; for example, application-specific time services. Satisfies: SRG-OS-000066-GPOS-00034, SRG-OS-000478-GPOS-00223
Fix Text
Obtain the approved DOD certificates from the appropriate authority. Use Keychain Access from "/Applications/Utilities" to add certificates to the System Keychain.
Check Content
To view a list of installed certificates, run the following command: /usr/bin/sudo /usr/bin/security dump-keychain | /usr/bin/grep labl | awk -F\" '{ print $4 }' If this list does not contain approved certificates, this is a finding.
The macOS system must implement cryptographic mechanisms to protect the confidentiality and integrity of all information at rest.
Discussion
Information at rest refers to the state of information when it is located on a secondary storage device (e.g., disk drive and tape drive) within an organizational information system. Mobile devices, laptops, desktops, and storage devices can be lost or stolen, and the contents of their data storage (e.g., hard drives and non-volatile memory) can be read, copied, or altered. By encrypting the system hard drive, the confidentiality and integrity of any data stored on the system is ensured. FileVault Disk Encryption mitigates this risk. Satisfies: SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183, SRG-OS-000405-GPOS-00184
Fix Text
Open System Preferences >> Security and Privacy and navigate to the "FileVault" tab. Use this panel to configure full-disk encryption. Alternately, from the command line, run the following command to enable "FileVault": /usr/bin/sudo /usr/bin/fdesetup enable After "FileVault" is initially set up, additional users can be added.
Check Content
To check if "FileVault 2" is enabled, run the following command: /usr/bin/sudo /usr/bin/fdesetup status If "FileVault" is "Off" and the device is a mobile device or the organization has determined that the drive must encrypt data at rest, this is a finding.
The macOS system must employ automated mechanisms to determine the state of system components with regard to flaw remediation using the following frequency: continuously where HBSS is used; 30 days for any additional internal network scans not covered by HBSS; and annually for external scans by Computer Network Defense Service Provider (CNDSP).
Discussion
An approved tool for continuous network scanning must be installed and configured to run. Without the use of automated mechanisms to scan for security flaws on a continuous and/or periodic basis, the operating system or other system components may remain vulnerable to the exploits presented by undetected software flaws. To support this requirement, the operating system may have an integrated solution incorporating continuous scanning using HBSS and periodic scanning using other tools, as specified in the requirement.
Fix Text
Install an approved HBSS solution onto the system.
Check Content
Ask the System Administrator (SA) or Information System Security Officer (ISSO) if an approved tool capable of continuous scanning is loaded on the system. The recommended system is the McAfee HBSS. If no such tool is installed on the system, this is a finding.
The macOS system must restrict the ability of individuals to use USB storage devices.
Discussion
External hard drives, such as USB, must be disabled for users. USB hard drives are a potential vector for malware and can be used to exfiltrate sensitive data if an approved data-loss prevention (DLP) solution is not installed.
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
If an approved HBSS DCM/DLP solution is installed, this is not applicable. To verify external USB drives are disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 3 harddisk-external If the result is not “harddisk-external" = ( eject, alert );”, this is a finding.
The macOS system must be configured to not allow iTunes file sharing.
Discussion
Connections to unauthorized iOS devices (e.g., iPhones, iPods, and iPads) open the system to possible compromise via exfiltration of system data. Disabling the iTunes file sharing blocks connections to iOS devices.
Fix Text
This setting is enforced using the “Restrictions Policy" configuration profile.
Check Content
If iTunes file sharing is enabled, unauthorized disclosure could occur. To verify that iTunes file sharing is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowiTunesFileSharing If the result is null or is not “allowiTunesFileSharing = 0”, this is a finding
The macOS system must not allow an unattended or automatic logon to the system.
Discussion
When automatic logons are enabled, the default user account is automatically logged on at boot time without prompting the user for a password. Even if the screen is later locked, a malicious user would be able to reboot the computer to log on. Disabling automatic logons mitigates this risk.
Fix Text
This setting is enforced using the "Login Window Policy" configuration profile.
Check Content
To check if the system is configured to automatically log on, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep DisableAutoLoginClient If "com.apple.login.mcx.DisableAutoLoginClient" is not set to "1", this is a finding.
The macOS system logon window must be configured to prompt for username and password, rather than show a list of users.
Discussion
The logon window must be configured to prompt all users for both a username and a password. By default, the system displays a list of known users at the logon screen. This gives an advantage to an attacker with physical access to the system, as the attacker would only have to guess the password for one of the listed accounts.
Fix Text
This setting is enforced using the "Login Window Policy" configuration profile.
Check Content
To check if the logon window is configured to prompt for user name and password, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep SHOWFULLNAME If there is no result, or "SHOWFULLNAME" is not set to "1", this is a finding.
The macOS firewall must have logging enabled.
Discussion
Firewall logging must be enabled. This ensures that malicious network activity will be logged to the system.
Fix Text
To enable the firewall logging, run the following command: /usr/bin/sudo /usr/libexec/ApplicationFirewall/socketfilterfw --setloggingmode on
Check Content
If HBSS is used, this is not applicable. To check if the macOS firewall has logging enabled, run the following command: /usr/libexec/ApplicationFirewall/socketfilterfw --getloggingmode | /usr/bin/grep on If the result does not show "on", this is a finding.
The macOS system must be configured so that Bluetooth devices are not allowed to wake the computer.
Discussion
A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Regardless of where the session lock is determined and implemented, once invoked, the session lock must remain in place until the user reauthenticates. No other activity aside from reauthentication must unlock the system.
Fix Text
Manually change this control on the computer by opening System Preferences >> Bluetooth. Click "Advanced" and ensure the "Allow Bluetooth devices to wake this computer" is not checked. This control is not necessary if Bluetooth has been completely disabled. The following can be run from the command line to disable "Remote Wake" for the current user: /usr/bin/defaults write /Users/`whoami`/Library/Preferences/ByHost/com.apple.Bluetooth.`/usr/sbin/system_profiler SPHardwareDataType | /usr/bin/grep "Hardware UUID" | /usr/bin/cut -c22-57`.plist RemoteWakeEnabled 0
Check Content
To check if the Bluetooth Remote Wake setting is disabled, run the following two commands as the primary user: /usr/bin/defaults -currentHost read com.apple.Bluetooth RemoteWakeEnabled /usr/bin/defaults read /Users/`whoami`/Library/Preferences/ByHost/com.apple.Bluetooth.`/usr/sbin/system_profiler SPHardwareDataType | grep "Hardware UUID" | cut -c22-57`.plist RemoteWakeEnabled If there is an error or nothing is returned, or the return value is "1" for either command, this is a finding.
The macOS system must be configured with Bluetooth Sharing disabled.
Discussion
Bluetooth sharing allows users to wirelessly transmit files between the macOS host and Bluetooth-enabled devices, including personally owned cellphones and tablets. A malicious user might introduce viruses or malware onto the system or extract sensitive files. Disabling Bluetooth Sharing mitigates this risk.
Fix Text
To disable Bluetooth Sharing, open System Preferences >> Sharing and uncheck the box next to "Bluetooth Sharing". This control is not necessary if Bluetooth has been completely disabled. The following can be run from the command line to disable "Bluetooth Sharing" for the current user: /usr/bin/defaults write /Users/`whoami`/Library/Preferences/ByHost/com.apple.Bluetooth.`/usr/sbin/system_profiler SPHardwareDataType | /usr/bin/grep "Hardware UUID" | /usr/bin/cut -c22-57`.plist PrefKeyServicesEnabled 0
Check Content
To check if Bluetooth Sharing is enabled, open System Preferences >> Sharing and verify that "Bluetooth Sharing" is not checked "ON". If it is "ON", this is a finding. The following command can be run from the command line: /usr/bin/defaults read /Users/`whoami`/Library/Preferences/ByHost/com.apple.Bluetooth.`/usr/sbin/system_profiler SPHardwareDataType | grep "Hardware UUID" | cut -c22-57`.plist PrefKeyServicesEnabled If there is an error or nothing is returned, or the return value is "1", this is a finding.
The macOS system must be configured to disable Remote Apple Events.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include but are not limited to games, software packages, tools, and demonstration software not related to requirements or providing a wide array of functionality not required for every mission but that cannot be disabled. Remote Apple Events must be disabled.
Fix Text
To disable Remote Apple Events, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.AEServer The system may need to be restarted for the update to take effect.
Check Content
To check if Remote Apple Events is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.AEServer If the results do not show the following, this is a finding. "com.apple.AEServer" => true
The macOS system must be configured with the sudoers file configured to authenticate users on a per -tty basis.
Discussion
The "sudo" command must be configured to prompt for the administrator's password at least once in each newly opened Terminal window or remote logon session, as this prevents a malicious user from taking advantage of an unlocked computer or an abandoned logon session to bypass the normal password prompt requirement. Without the "tty_tickets" option, all open local and remote logon sessions would be authenticated to use sudo without a password for the duration of the configured password timeout window.
Fix Text
Edit the "/etc/sudoers" file to contain the line: Defaults tty_tickets This line can be placed in the defaults section or at the end of the file.
Check Content
To check if the "tty_tickets" option is set for "/usr/bin/sudo", run the following command: /usr/bin/sudo /usr/bin/grep tty_tickets /etc/sudoers If there is no result, this is a finding.
The macOS Application Firewall must be enabled.
Discussion
The Application Firewall is the built-in firewall that comes with macOS and must be enabled. Firewalls protect computers from network attacks by blocking or limiting access to open network ports. Application firewalls limit which applications are allowed to communicate over the network.
Fix Text
To enable the firewall, run the following command: /usr/bin/sudo /usr/libexec/ApplicationFirewall/socketfilterfw --setglobalstate on
Check Content
If an approved HBSS solution is installed, this is not applicable. To check if the macOS firewall has been enabled, run the following command: /usr/bin/sudo /usr/libexec/ApplicationFirewall/socketfilterfw --getglobalstate If the result is "disabled", this is a finding.
The macOS system must be configured with all public directories owned by root or an application account.
Discussion
All public directories must be owned by "root", the local admin user, or an application account. Directory owners have permission to delete any files contained in that directory, even if the files are owned by other user accounts. By setting the owner to an administrator or application account, regular users will not be permitted to delete each other's files.
Fix Text
To change the ownership of any finding, run the following command: /usr/bin/sudo find / -type d -perm +o+w -not -uid 0 -exec chown root {} \;
Check Content
To display all directories that are writable by all and not owned by "root", run the following command: /usr/bin/sudo find / -type d -perm +o+w -not -uid 0 If anything is returned, and those directories are not owned by root or application account, this is a finding.
The macOS system must be configured with the finger service disabled.
Discussion
The "finger" service has had several security vulnerabilities in the past and is not a necessary service. It is disabled by default; enabling it would increase the attack surface of the system.
Fix Text
To disable the "finger" service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.fingerd The system may need to be restarted for the update to take effect.
Check Content
To check if the "finger" service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.fingerd If the results do not show the following, this is a finding: "com.apple.fingerd" => true
The macOS system must be configured with the sticky bit set on all public directories.
Discussion
The sticky bit must be set on all public directories, as it prevents users with write access to the directory from deleting or renaming files that belong to other users inside it.
Fix Text
Run the following command to set the "sticky bit" on all world-writable directories: /usr/bin/sudo /usr/bin/find / -type d \( -perm -0002 -a ! -perm -1000 \) -exec chmod +t {} \;
Check Content
Run the following command to view all world-writable directories that do not have the "sticky bit" set: /usr/bin/sudo /usr/bin/find / -type d \( -perm -0002 -a ! -perm -1000 \) If anything is returned, this is a finding.
The macOS system must be configured with the prompt for Apple ID and iCloud disabled.
Discussion
The prompt for Apple ID and iCloud must be disabled, as it might mislead new users into creating unwanted Apple IDs and iCloud storage accounts upon their first logon.
Fix Text
This setting is enforced using the “Login Window Policy" configuration profile.
Check Content
To check if the system is configured to skip cloud setup, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep SkipCloudSetup If “SkipCloudSetup" is not set to "1", this is a finding. To check if the prompt for "Apple ID" and "iCloud" are disabled for new users, run the following command: /usr/bin/sudo /usr/bin/defaults read /System/Library/User\ Template/English.lproj/Library/Preferences/com.apple.SetupAssistant If there is no result, if it prints out that the domain "does not exist", or the results do not include "DidSeeCloudSetup = 1 AND LastSeenCloudProductVersion = 10.12", this is a finding.
The macOS system must be configured so that users do not have Apple IDs signed into iCloud.
Discussion
Users should not sign into iCloud, as this leads to the possibility that sensitive data could be saved to iCloud storage or that users could inadvertently introduce viruses or malware previously saved to iCloud from other systems.
Fix Text
This must be resolved manually. With the affected user logged on, open System Preferences >> iCloud. Choose "Sign Out".
Check Content
To see if any user account has configured an Apple ID for iCloud usage, run the following command: /usr/bin/sudo find /Users/ -name 'MobileMeAccounts.plist' -exec /usr/bin/defaults read '{}' \; If the results show any accounts listed, this is a finding.
The macOS system must be configured with iTunes Music Sharing disabled.
Discussion
When iTunes Music Sharing is enabled, the computer starts a network listening service that shares the contents of the user's music collection with other users in the same subnet. Unnecessary network services should always be disabled because they increase the attack surface of the system. Disabling iTunes Music Sharing mitigates this risk.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
To check if iTunes Music Sharing is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep disableSharedMusic If the return is null or does not contain “disableSharedMusic = 1” this is a finding.
All setuid executables on the macOS system must be documented.
Discussion
Very few of the executables that come preinstalled on the macOS host have the "setuid" bit set, and administrators should never add the "setuid" bit to any executable that does not already have it set by the vendor. Executables with the "setuid" bit set allow anyone that executes them to be temporarily assigned the UID of the file owner. In practice, this almost always is the root account. While some vendors depend on this file attribute for proper operation, security problems can result if "setuid" is assigned to programs allowing reading and writing of files, or shell escapes, as this could lead to unprivileged users gaining privileged access to files and directories on the system.
Fix Text
Document all of the files with the "setuid" bit set. Remove any undocumented files.
Check Content
If available, provide a list of "setuids" provided by a vendor. To list all of the files with the "setuid" bit set, run the following command to send all results to a file named "suidfilelist": /usr/bin/sudo find / -perm -4000 -exec /bin/ls -ldb {} \; > suidfilelist If any of the files listed are not documented as needing to have the "setuid" bit set by the vendor, this is a finding.
The macOS system must not accept source-routed IPv4 packets.
Discussion
A source-routed packet attempts to specify the network path the packet should take. If the system is not configured to block the incoming source-routed packets, an attacker can redirect the system's network traffic. Configuring the system to drop incoming source-routed IPv4 packets mitigates this risk.
Fix Text
To configure the system to not accept "source-routed" packets, add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet.ip.accept_sourceroute=0
Check Content
To check if the system is configured to accept "source-routed" packets, run the following command: sysctl net.inet.ip.accept_sourceroute If the value is not "0", this is a finding.
The macOS system must ignore IPv4 ICMP redirect messages.
Discussion
ICMP redirects are broadcast to reshape network traffic. A malicious user could craft fake redirect packets and try to force all network traffic to pass through a network sniffer. If the system is not configured to ignore these packets, it could be susceptible to this kind of attack.
Fix Text
To configure the system to ignore "ICMP redirect" messages, add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet.icmp.drop_redirect=1
Check Content
To check if the system is configured to ignore "ICMP redirect" messages, run the following command: sysctl net.inet.icmp.drop_redirect If the value is not "1", this is a finding.
The macOS system must not have IP forwarding for IPv4 enabled.
Discussion
IP forwarding for IPv4 must not be enabled, as only authorized systems should be permitted to operate as routers.
Fix Text
To configure the system to disable "IP forwarding", add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet.ip.forwarding=0
Check Content
To check if "IP forwarding" is enabled, run the following command: sysctl net.inet.ip.forwarding If the values are not "0", this is a finding.
The macOS system must not have IP forwarding for IPv6 enabled.
Discussion
IP forwarding for IPv6 must not be enabled, as only authorized systems should be permitted to operate as routers.
Fix Text
To configure the system to disable "IP forwarding", add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet6.ip6.forwarding=0
Check Content
To check if "IP forwarding" is enabled, run the following command: sysctl net.inet6.ip6.forwarding If the values are not "0", this is a finding.
The macOS system must not send IPv4 ICMP redirects by default.
Discussion
ICMP redirects are broadcast to reshape network traffic. A malicious user could use the system to send fake redirect packets and try to force all network traffic to pass through a network sniffer. Disabling ICMP redirect broadcasts mitigates this risk.
Fix Text
To configure the system to not send ICMP redirects, add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet.ip.redirect=0
Check Content
To check if the system is configured to send ICMP redirects, run the following command: sysctl net.inet.ip.redirect If the values are not set to "0", this is a finding.
The macOS system must not send IPv6 ICMP redirects by default.
Discussion
ICMP redirects are broadcast to reshape network traffic. A malicious user could use the system to send fake redirect packets and try to force all network traffic to pass through a network sniffer. Disabling ICMP redirect broadcasts mitigates this risk.
Fix Text
To configure the system to not send ICMP redirects, add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet6.ip6.redirect=0
Check Content
To check if the system is configured to send ICMP redirects, run the following command: sysctl net.inet6.ip6.redirect If the values are not set to "0", this is a finding.
The macOS system must prevent local applications from generating source-routed packets.
Discussion
A source-routed packet attempts to specify the network path that the system should take. If the system is not configured to block the sending of source-routed packets, an attacker can redirect the system's network traffic.
Fix Text
To configure the system to not forward source-routed packets, add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet.ip.sourceroute=0
Check Content
To check if the system is configured to forward source-routed packets, run the following command: sysctl net.inet.ip.sourceroute If the value is not set to "0", this is a finding.
The macOS system must not process Internet Control Message Protocol [ICMP] timestamp requests.
Discussion
ICMP timestamp requests reveal information about the system and can be used to determine which operating system is installed. Precise time data can also be used to launch time-based attacks against the system. Configuring the system to drop incoming ICMPv4 timestamp requests mitigates these risks.
Fix Text
To disable ICMP timestamp responses, add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet.icmp.timestamp=0
Check Content
To check if the system is configured to process ICMP timestamp requests, run the following command: sysctl net.inet.icmp.timestamp If the value is not set to "0", this is a finding.
The macOS system must have unused network devices disabled.
Discussion
If an unused network device is left enabled, a user might be able to activate it at a later time. Unused network devices should be disabled.
Fix Text
To disable a network device, run the following command, substituting the name of the device in place of "'<networkservice>'": /usr/bin/sudo /usr/sbin/networksetup -setnetworkserviceenabled '<networkservice>' off
Check Content
To list the network devices that are enabled on the system, run the following command: /usr/bin/sudo /usr/sbin/networksetup -listallnetworkservices A disabled device will have an asterisk in front of its name. If any listed device that is not in use is missing this asterisk, this is a finding.
The macOS system must be configured to disable Internet Sharing.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. Internet Sharing must be disabled.
Fix Text
To disable Internet Sharing, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.NetworkSharing The system may need to be restarted for the update to take effect.
Check Content
To check if Internet Sharing is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep com.apple.NetworkSharing If the results do not show the following, this is a finding: "com.apple.NetworkSharing" => true
The macOS system must be configured to disable Web Sharing.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. Web Sharing is non-essential and must be disabled.
Fix Text
To disable Web Sharing, run the following command: /usr/bin/sudo /bin/launchctl disable system/org.apache.httpd The system may need to be restarted for the update to take effect.
Check Content
To check if Web Sharing is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system | /usr/bin/grep org.apache.httpd If the results do not show the following, this is a finding: "org.apache.httpd" => true
The macOS system must enforce an account lockout time period of 15 minutes in which a user makes three consecutive invalid logon attempts.
Discussion
Setting a lockout time period of 15 minutes is an effective deterrent against brute forcing that also makes allowances for legitimate mistakes by users. When three invalid logon attempts are made, the account will be locked.
Fix Text
This setting may be enforced using the "Passcode Policy" configuration profile or by a directory service. The following two lines within the configuration enforce lockout expiration to "15" minutes: <key>autoEnableInSeconds</key> <integer>900</integer> To set the password policy without a configuration profile, run the following command to save a copy of the current "pwpolicy" account policy file: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies | tail -n +2 > pwpolicy.plist Open the generated file in a text editor and ensure it contains the following text after the opening <dict> tag and before the closing </dict> tag. Replace <dict/> first with <dict></dict> if necessary. <key>policyCategoryAuthentication</key> <array> <dict> <key>policyContent</key> <string>(policyAttributeFailedAuthentications < policyAttributeMaximumFailedAuthentications) OR (policyAttributeCurrentTime > (policyAttributeLastFailedAuthenticationTime + autoEnableInSeconds))</string> <key>policyIdentifier</key> <string>Authentication Lockout</string> <key>policyParameters</key> <dict> <key>autoEnableInSeconds</key> <integer>900</integer> <key>policyAttributeMaximumFailedAuthentications</key> <integer>3</integer> </dict> </dict> </array> If the line "<key>policyCategoryAuthentication</key>" already exists, the following text should be used instead and inserted after the first <array> tag that follows it: <dict> <key>policyContent</key> <string>(policyAttributeFailedAuthentications < policyAttributeMaximumFailedAuthentications) OR (policyAttributeCurrentTime > (policyAttributeLastFailedAuthenticationTime + autoEnableInSeconds))</string> <key>policyIdentifier</key> <string>Authentication Lockout</string> <key>policyParameters</key> <dict> <key>autoEnableInSeconds</key> <integer>900</integer> <key>policyAttributeMaximumFailedAuthentications</key> <integer>3</integer> </dict> </dict> After saving the file and exiting to the command prompt, run the following command to load the new policy file: /usr/bin/sudo /usr/bin/pwpolicy setaccountpolicies pwpolicy.plist Note: Updates to password restrictions must be thoroughly evaluated in a test environment. Mistakes in configuration may block password change and local user creation operations, as well as lock out all local users, including administrators.
Check Content
Password policy can be set with a configuration profile or the "pwpolicy" utility. If password policy is set with a configuration profile, run the following command to check if the system has the correct setting for the logon reset timer: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep minutesUntilFailedLoginReset If the return is null or not “minutesUntilFailedLoginReset = 15”, this is a finding. If password policy is set with the "pwpolicy" utility, the variable names may vary depending on how the policy was set. To check if the password policy is configured to disable an account for 15 minutes after 3 unsuccessful logon attempts, run the following command to output the password policy to the screen: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies Look for the line "<key>policyCategoryAuthentication</key>". If this does not exist, and password policy is not controlled by a directory service, this is a finding. In the array that follows, there should be one or more <dict> sections that describe policy checks. One should contain a <string> that allows users to log on if "policyAttributeFailedAuthentications" is less than "policyAttributeMaximumFailedAuthentications". Under policyParameters, "policyAttributeMaximumFailedAuthentications" should be set to "3". If "policyAttributeMaximumFailedAuthentications" is not set to "3", this is a finding. In the same check or in another <dict> section, there should be a <string> that allows users to log on if the "policyAttributeCurrentTime" is greater than the result of adding "15" minutes (900 seconds) to "policyAttributeLastFailedAuthenticationTime". The check might use a variable defined in its "policyParameters" section. If the check does not exist or if the check adds too great an amount of time, this is a finding.
The macOS system must enforce account lockout after the limit of three consecutive invalid logon attempts by a user.
Discussion
By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute forcing, is reduced. Limits are imposed by locking the account.
Fix Text
This setting may be enforced using the "Passcode Policy" configuration profile or by a directory service. To set the password policy without a configuration profile, run the following command to save a copy of the current "pwpolicy" account policy file: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies | tail -n +2 > pwpolicy.plist Open the generated file in a text editor and ensure it contains the following text after the opening <dict> tag and before the closing </dict> tag. Replace <dict/> first with <dict></dict> if necessary. <key>policyCategoryAuthentication</key> <array> <dict> <key>policyContent</key> <string>(policyAttributeFailedAuthentications < policyAttributeMaximumFailedAuthentications) OR (policyAttributeCurrentTime > (policyAttributeLastFailedAuthenticationTime + autoEnableInSeconds))</string> <key>policyIdentifier</key> <string>Authentication Lockout</string> <key>policyParameters</key> <dict> <key>autoEnableInSeconds</key> <integer>900</integer> <key>policyAttributeMaximumFailedAuthentications</key> <integer>3</integer> </dict> </dict> </array> If the line "<key>policyCategoryAuthentication</key>" already exists, the following text should be used instead and inserted after the first <array> tag that follows it: <dict> <key>policyContent</key> <string>(policyAttributeFailedAuthentications < policyAttributeMaximumFailedAuthentications) OR (policyAttributeCurrentTime > (policyAttributeLastFailedAuthenticationTime + autoEnableInSeconds))</string> <key>policyIdentifier</key> <string>Authentication Lockout</string> <key>policyParameters</key> <dict> <key>autoEnableInSeconds</key> <integer>900</integer> <key>policyAttributeMaximumFailedAuthentications</key> <integer>3</integer> </dict> </dict> After saving the file and exiting to the command prompt, run the following command to load the new policy file: /usr/bin/sudo /usr/bin/pwpolicy setaccountpolicies pwpolicy.plist <key>policyCategoryAuthentication</key> <array> <dict> <key>policyContent</key> <string>(policyAttributeFailedAuthentications < policyAttributeMaximumFailedAuthentications) OR (policyAttributeCurrentTime > (policyAttributeLastFailedAuthenticationTime + autoEnableInSeconds))</string> <key>policyIdentifier</key> <string>Authentication Lockout</string> <key>policyParameters</key> <dict> <key>autoEnableInSeconds</key> <integer>900</integer> <key>policyAttributeMaximumFailedAuthentications</key> <integer>3</integer> </dict> </dict> </array> If the line <key>policyCategoryAuthentication</key> already exists, the following text should be used instead and inserted after the first <array> tag that follows it: <dict> <key>policyContent</key> <string>(policyAttributeFailedAuthentications < policyAttributeMaximumFailedAuthentications) OR (policyAttributeCurrentTime > (policyAttributeLastFailedAuthenticationTime + autoEnableInSeconds))</string> <key>policyIdentifier</key> <string>Authentication Lockout</string> <key>policyParameters</key> <dict> <key>autoEnableInSeconds</key> <integer>900</integer> <key>policyAttributeMaximumFailedAuthentications</key> <integer>3</integer> </dict> </dict> After saving the file and exiting to the command prompt, run the following command to load the new policy file: /usr/bin/sudo /usr/bin/pwpolicy setaccountpolicies pwpolicy.plist Note: Updates to password restrictions must be thoroughly evaluated in a test environment. Mistakes in configuration or bugs in OS X may block password change and local user creation operations, as well as lock out all local users, including administrators.
Check Content
Password policy can be set with a configuration profile or the "pwpolicy" utility. If password policy is set with a configuration profile, run the following command to check if the system has the correct setting for the number of permitted failed logon attempts: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep maxFailedAttempts If the return is null, or not, “maxFailedAttempts = 3”, this is a finding. If password policy is set with the "pwpolicy" utility, the variable names may vary depending on how the policy was set. To check if the password policy is configured to disable an account for 15 minutes after 3 unsuccessful logon attempts, run the following command to output the password policy to the screen: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies Look for the line "<key>policyCategoryAuthentication</key>". If this does not exist, and password policy is not controlled by a directory service, this is a finding. In the array that follows, there should be one or more <dict> sections that describe policy checks. One should contain a <string> that allows users to log on if "policyAttributeFailedAuthentications" is less than "policyAttributeMaximumFailedAuthentications". Under policyParameters, "policyAttributeMaximumFailedAuthentications" should be set to "3". If "policyAttributeMaximumFailedAuthentications" is not set to "3", this is a finding. In the same check or in another <dict> section, there should be a <string> that allows users to log on if the "policyAttributeCurrentTime" is greater than the result of adding "15" minutes (900 seconds) to "policyAttributeLastFailedAuthenticationTime". The check might use a variable defined in its policyParameters section. If the check does not exist or if the check adds too great an amount of time, this is a finding.
The macOS system must enforce the limit of three consecutive invalid logon attempts by a user before the user account is locked.
Discussion
By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute forcing, is reduced. Limits are imposed by locking the account. Setting a lockout expiration of 15 minutes is an effective deterrent against brute forcing that also makes allowances for legitimate mistakes by users.
Fix Text
This setting may be enforced using the "Passcode Policy" configuration profile or by a directory service. To set the password policy without a configuration profile, run the following command to save a copy of the current "pwpolicy" account policy file: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies | tail -n +2 > pwpolicy.plist Open the generated file in a text editor and ensure it contains the following text after the opening <dict> tag and before the closing </dict> tag. Replace <dict/> first with <dict></dict> if necessary. <key>policyCategoryAuthentication</key> <array> <dict> <key>policyContent</key> <string>(policyAttributeFailedAuthentications < policyAttributeMaximumFailedAuthentications) OR (policyAttributeCurrentTime > (policyAttributeLastFailedAuthenticationTime + autoEnableInSeconds))</string> <key>policyIdentifier</key> <string>Authentication Lockout</string> <key>policyParameters</key> <dict> <key>autoEnableInSeconds</key> <integer>900</integer> <key>policyAttributeMaximumFailedAuthentications</key> <integer>3</integer> </dict> </dict> </array> If the line "<key>policyCategoryAuthentication</key>" already exists, the following text should be used instead and inserted after the first <array> tag that follows it: <dict> <key>policyContent</key> <string>(policyAttributeFailedAuthentications < policyAttributeMaximumFailedAuthentications) OR (policyAttributeCurrentTime > (policyAttributeLastFailedAuthenticationTime + autoEnableInSeconds))</string> <key>policyIdentifier</key> <string>Authentication Lockout</string> <key>policyParameters</key> <dict> <key>autoEnableInSeconds</key> <integer>900</integer> <key>policyAttributeMaximumFailedAuthentications</key> <integer>3</integer> </dict> </dict> After saving the file and exiting to the command prompt, run the following command to load the new policy file: /usr/bin/sudo /usr/bin/pwpolicy setaccountpolicies pwpolicy.plist Note: Updates to password restrictions must be thoroughly evaluated in a test environment. Mistakes in configuration or bugs in OS X may block password change and local user creation operations, as well as lock out all local users, including administrators.
Check Content
Password policy can be set with a configuration profile or the "pwpolicy" utility. If password policy is set with a configuration profile, run the following command to check if the system has the correct setting for the number of permitted failed logon attempts and the logon reset timer: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep 'maxFailedAttempts\|minutesUntilFailedLoginReset' If "maxFailedAttempts" is not set to "3" and "minutesUntilFailedLoginReset" is not set to "15", this is a finding. If password policy is set with the "pwpolicy" utility, the variable names may vary depending on how the policy was set. To check if the password policy is configured to disable an account for 15 minutes after 3 unsuccessful logon attempts, run the following command to output the password policy to the screen: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies Look for the line "<key>policyCategoryAuthentication</key>". If this does not exist, and password policy is not controlled by a directory service, this is a finding. In the array that follows, there should be one or more <dict> sections that describe policy checks. One should contain a <string> that allows users to log on if "policyAttributeFailedAuthentications" is less than "policyAttributeMaximumFailedAuthentications". Under policyParameters, "policyAttributeMaximumFailedAuthentications" should be set to "3". If "policyAttributeMaximumFailedAuthentications" is not set to "3", this is a finding. In the same check or in another <dict> section, there should be a <string> that allows users to log on if the "policyAttributeCurrentTime" is greater than the result of adding "15" minutes (900 seconds) to "policyAttributeLastFailedAuthenticationTime". The check might use a variable defined in its "policyParameters" section. If the check does not exist or if the check adds too great an amount of time, this is a finding.
The macOS system must shut down by default upon audit failure (unless availability is an overriding concern).
Discussion
The audit service should shut down the computer if it is unable to audit system events. Once audit failure occurs, user and system activity is no longer recorded and malicious activity could go undetected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. Responses to audit failure depend on the nature of the failure mode. When availability is an overriding concern, other approved actions in response to an audit failure are as follows: (i) If the failure was caused by the lack of audit record storage capacity, the operating system must continue generating audit records if possible (automatically restarting the audit service if necessary), overwriting the oldest audit records in a first-in-first-out manner. (ii) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, the operating system must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server.
Fix Text
Edit the "/etc/security/audit_control file" and change the value for policy to include the setting "ahlt". To do this programmatically, run the following command: sudo /usr/bin/sed -i.bak '/^policy/ s/$/,ahlt/' /etc/security/audit_control; sudo /usr/sbin/audit -s
Check Content
To view the setting for the audit control system, run the following command: sudo /usr/bin/grep ^policy /etc/security/audit_control | /usr/bin/grep ahlt If there is no result, this is a finding.
The macOS system must use a DoD antivirus program.
Discussion
An approved antivirus product must be installed and configured to run. Malicious software can establish a base on individual desktops and servers. Employing an automated mechanism to detect this type of software will aid in elimination of the software from the operating system.
Fix Text
Install an approved antivirus solution onto the system.
Check Content
Ask the System Administrator (SA) or Information System Security Officer (ISSO) if an approved antivirus solution is loaded on the system. The antivirus solution may be bundled with an approved host-based security solution. If there is no local antivirus solution installed on the system, this is a finding.
The macOS system must be configured to disable AirDrop.
Discussion
To prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. AirDrop must be disabled.
Fix Text
Disabling AirDrop is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if AirDrop has been disabled, run the following command: sudo /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep DisableAirDrop If the result is not "DisableAirDrop = 1", this is a finding.
The macOS system must be integrated into a directory services infrastructure.
Discussion
Distinct user account databases on each separate system cause problems with username and password policy enforcement. Most approved directory services infrastructure solutions allow centralized management of users and passwords.
Fix Text
Integrate the system into an existing directory services infrastructure.
Check Content
To determine if the system is integrated to a directory service, ask the System Administrator (SA) or Information System Security Officer (ISSO) or run the following command: /usr/bin/sudo dscl localhost -list . | /usr/bin/grep -vE '(Contact | Search | Local)' If nothing is returned, or if the system is not integrated into a directory service infrastructure, this is a finding.
The macOS system must enforce a 60-day maximum password lifetime restriction.
Discussion
Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. One method of minimizing this risk is to use complex passwords and periodically change them. If the operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the operating system passwords could be compromised.
Fix Text
This setting may be enforced using the "Passcode Policy" configuration profile or by a directory service. To set the password policy without a configuration profile, run the following command to save a copy of the current "pwpolicy" account policy file: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies | tail -n +2 > pwpolicy.plist Open the generated file in a text editor. If the file does not yet contain any policy settings, replace <dict/> with <dict></dict>. If there already is a policy block that refers to password expiration, ensure it is set to "60" days. If the line "<key>policyCategoryPasswordChange</key>" is not present in the file, add the following text immediately after the opening <dict> tag in the file: <key>policyCategoryPasswordChange</key> <array> <dict> <key>policyContent</key> <string>policyAttributeCurrentTime > policyAttributeLastPasswordChangeTime + (policyAttributeExpiresEveryNDays * 24 * 60 * 60)</string> <key>policyIdentifier</key> <string>Password Change Interval</string> <key>policyParameters</key> <dict> <key>policyAttributeExpiresEveryNDays</key> <integer>60</integer> </dict> </dict> </array> If the line "<key>policyCategoryPasswordChange</key>" is already present in the file, the following text should be added just after the opening <array> tag that follows the line instead: <dict> <key>policyContent</key> <string>policyAttributeCurrentTime > policyAttributeLastPasswordChangeTime + (policyAttributeExpiresEveryNDays * 24 * 60 * 60)</string> <key>policyIdentifier</key> <string>Password Change Interval</string> <key>policyParameters</key> <dict> <key>policyAttributeExpiresEveryNDays</key> <integer>60</integer> </dict> </dict> After saving the file and exiting to the command prompt, run the following command to load the new policy file: /usr/bin/sudo /usr/bin/pwpolicy setaccountpolicies pwpolicy.plist Note: Updates to password restrictions must be thoroughly evaluated in a test environment. Mistakes in configuration may block password change and local user creation operations, as well as lock out all local users, including administrators.
Check Content
Password policy can be set with a configuration profile or the "pwpolicy" utility. If password policy is set with a configuration profile, run the following command to check if the system is configured to require users to change their passwords every 60 days: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep maxPINAgeInDays If the return is null, or is not “maxPINAgeInDays = 60” or set to a smaller value, this is a finding. If password policy is set with the "pwpolicy" utility, run the following command instead: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies Look for the line <key>policyCategoryPasswordChange</key>. If it does not exist, and password policy is not controlled by a directory service, this is a finding. Otherwise, in the array section that follows it, there should be a <dict> section that contains a check <string> that compares the variable "policyAttributeLastPasswordChangeTime" to the variable "policyAttributeCurrentTime". It may contain additional variables defined in the "policyParameters" section that follows it. All comparisons are done in seconds. If this check allows users to log in with passwords older than "60" days, or if no such check exists, this is a finding.
The macOS system must prohibit password reuse for a minimum of five generations.
Discussion
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. If the information system or application allows the user to consecutively reuse their password when that password has exceeded its defined lifetime, the end result is a password that is not changed as per policy requirements.
Fix Text
This setting may be enforced using the "Passcode Policy" configuration profile or by a directory service. To set the password policy without a configuration profile, run the following command to save a copy of the current "pwpolicy" account policy file: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies | tail -n +2 > pwpolicy.plist Open the generated file in a text editor. If the file does not yet contain any policy settings, replace <dict/> with <dict></dict>. If there already is a policy block that refers to password history, ensure it is set to "5". If the line "<key>policyCategoryPasswordContent</key>" is not present in the file, add the following text immediately after the opening <dict> tag in the file: <key>policyCategoryPasswordContent</key> <array> <dict> <key>policyContent</key> <string>none policyAttributePasswordHashes in policyAttributePasswordHistory</string> <key>policyIdentifier</key> <string>Password History</string> <key>policyParameters</key> <dict> <key>policyAttributePasswordHistoryDepth</key> <integer>5</integer> </dict> </dict> </array> If the line "<key>policyCategoryPasswordContent</key>" is already present in the file, the following text should be added just after the opening <array> tag that follows the line instead: <dict> <key>policyContent</key> <string>none policyAttributePasswordHashes in policyAttributePasswordHistory</string> <key>policyIdentifier</key> <string>Password History</string> <key>policyParameters</key> <dict> <key>policyAttributePasswordHistoryDepth</key> <integer>5</integer> </dict> </dict> After saving the file and exiting to the command prompt, run the following command to load the new policy file: /usr/bin/sudo /usr/bin/pwpolicy setaccountpolicies pwpolicy.plist Note: Updates to password restrictions must be thoroughly evaluated in a test environment. Mistakes in configuration may block password change and local user creation operations, as well as lock out all local users, including administrators.
Check Content
Password policy can be set with the "Password Policy" configuration profile or the "pwpolicy" utility. If password policy is set with a configuration profile, run the following command to check if the system is configured to require that users cannot reuse one of their five previously used passwords: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep pinHistory If the return in null or not “pinHistory = 5” or greater, this is a finding. If password policy is set with the "pwpolicy" utility, run the following command instead: /usr/bin/sudo /usr/bin/pwpolicy getaccountpolicies Look for the line "<key>policyCategoryPasswordContent</key>". If it does not exist, and password policy is not controlled by a directory service, this is a finding. Otherwise, in the array section that follows it, there should be a <dict> section that contains a check <string> such as "<string>none policyAttributePasswordHashes in policyAttributePasswordHistory</string>". This searches for the hash of the user-entered password in the list of previous password hashes. In the "policyParameters" section that follows it, "policyAttributePasswordHistoryDepth" must be set to "5" or greater. If this parameter is not set to "5" or greater, or if no such check exists, this is a finding.
The macOS system must be configured with system log files owned by root and group-owned by wheel or admin.
Discussion
System logs should only be readable by root or admin users. System logs frequently contain sensitive information that could be used by an attacker. Setting the correct owner mitigates this risk.
Fix Text
For any log file that returns an incorrect owner or group value, run the following command: /usr/bin/sudo chown root:wheel [log file] [log file] is the full path to the log file in question. If the file is managed by "newsyslog", find the configuration line in the directory "/etc/newsyslog.d/" or the file "/etc/newsyslog.conf" and ensure that the owner:group column is set to "root:wheel" or the appropriate service user account and group. If the file is managed by "aslmanager", find the configuration line in the directory "/etc/asl/" or the file "/etc/asl.conf" and ensure that "uid" and "gid" options are either not present or are set to a service user account and group respectively.
Check Content
Log files are controlled by "newsyslog" and "aslmanager". These commands check for log files that exist on the system and print out the log with corresponding ownership. Run them from inside "/var/log": /usr/bin/sudo stat -f '%Su:%Sg:%N' $(/usr/bin/grep -v '^#' /etc/newsyslog.conf | awk '{ print $1 }') 2> /dev/null /usr/bin/sudo stat -f '%Su:%Sg:%N' $(/usr/bin/grep -e '^>' /etc/asl.conf /etc/asl/* | awk '{ print $2 }') 2> /dev/null If there are any system log files that are not owned by "root" and group-owned by "wheel" or admin, this is a finding. Service logs may be owned by the service user account or group.
The macOS system must be configured with system log files set to mode 640 or less permissive.
Discussion
System logs should only be readable by root or admin users. System logs frequently contain sensitive information that could be used by an attacker. Setting the correct permissions mitigates this risk.
Fix Text
For any log file that returns an incorrect permission value, run the following command: /usr/bin/sudo chmod 640 [log file] [log file] is the full path to the log file in question. If the file is managed by "newsyslog", find the configuration line in the directory "/etc/newsyslog.d/" or the file "/etc/newsyslog.conf" and edit the mode column to be "640" or less permissive. If the file is managed by "aslmanager", find the configuration line in the directory "/etc/asl/" or the file "/etc/asl.conf" and add or edit the mode option to be "mode=0640" or less permissive.
Check Content
These commands check for log files that exist on the system and print out the log with corresponding permissions. Run them from inside "/var/log": /usr/bin/sudo stat -f '%A:%N' $(/usr/bin/grep -v '^#' /etc/newsyslog.conf | awk '{ print $1 }') 2> /dev/null /usr/bin/sudo stat -f '%A:%N' $(/usr/bin/grep -e '^>' /etc/asl.conf /etc/asl/* | awk '{ print $2 }') 2> /dev/null The correct permissions on log files should be "640" or less permissive for system logs. Any file with more permissive settings is a finding.
The macOS system must be configured with access control lists (ACLs) for system log files to be set correctly.
Discussion
System logs should only be readable by root or admin users. System logs frequently contain sensitive information that could be used by an attacker. Setting the correct ACLs mitigates this risk.
Fix Text
For any log file that returns an ACL, run the following command: /usr/bin/sudo chmod -N [log file] [log file] is the full path to the log file in question.
Check Content
These commands check for log files that exist on the system and print out the list of ACLs if there are any. /usr/bin/sudo ls -ld@ $(/usr/bin/grep -v '^#' /etc/newsyslog.conf | awk '{ print $1 }') 2> /dev/null /usr/bin/sudo ls -ld@ $(/usr/bin/grep -e '^>' /etc/asl.conf /etc/asl/* | awk '{ print $2 }') 2> /dev/null ACLs will be listed under any file that may contain them (i.e., "0: group:admin allow list,readattr,reaadextattr,readsecurity"). If any system log file contains this information, this is a finding.
The macOS system must audit the enforcement actions used to restrict access associated with changes to the system.
Discussion
By auditing access restriction enforcement, changes to application and OS configuration files can be audited. Without auditing the enforcement of access restrictions, it will be difficult to identify attempted attacks and an audit trail will not be available for forensic investigation. Enforcement actions are the methods or mechanisms used to prevent unauthorized changes to configuration settings. Enforcement action methods may be as simple as denying access to a file based on the application of file permissions (access restriction). Audit items may consist of lists of actions blocked by access restrictions or changes identified after the fact. Satisfies: SRG-OS-000365-GPOS-00152, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-OS-000474-GPOS-00219
Fix Text
To set the audit flags to the recommended setting, run the following command to add the flags "fm", "-fr", and "-fw" all at once: /usr/bin/sudo /usr/bin/sed -i.bak '/^flags/ s/$/,fm,-fr,-fw/' /etc/security/audit_control; /usr/bin/sudo /usr/sbin/audit -s A text editor may also be used to implement the required updates to the "/etc/security/audit_control" file.
Check Content
To view the currently configured flags for the audit daemon, run the following command: /usr/bin/sudo /usr/bin/grep ^flags /etc/security/audit_control Enforcement actions are logged by way of the "fm" flag, which audits permission changes, and "-fr" and "-fw", which denote failed attempts to read or write to a file. If "fm", "-fr", and "-fw" are not listed in the result of the check, this is a finding.
The macOS system must be configured to lock the user session when a smart token is removed.
Discussion
A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Rather than be forced to wait for a period of time to expire before the user session can be locked, operating systems need to provide users with the ability to manually invoke a session lock so users may secure their session should they need to temporarily vacate the immediate physical vicinity.
Fix Text
This is now in the smartcard payload. <key>tokenRemovalAction</key> <integer>1</integer>
Check Content
To check if support for session locking with removal of a token is enabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep "tokenRemovalAction = 1;" If there is no result, this is a finding.
The macOS system must enable certificate for smartcards.
Discussion
To prevent untrusted certificates the certificates on a smartcard card must be valid in these ways: its issuer is system-trusted, the certificate is not expired, its "valid-after" date is in the past, and it passes CRL and OCSP checking.
Fix Text
This setting is enforced using the "Smartcard" configuration profile.
Check Content
To view the setting for the smartcard certification configuration, run the following command: sudo /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep checkCertificateTrust If the output is null or not "checkCertificateTrust = 1;" this is a finding.
The macOS system must prohibit user installation of software without explicit privileged status.
Discussion
Allowing regular users to install software, without explicit privileges, creates the risk that untested or potentially malicious software will be installed on the system. Explicit privileges (escalated or administrative privileges) provide the regular user with explicit capabilities and control that exceeds the rights of a regular user. Operating system functionality will vary, and while users are not permitted to install unapproved software, there may be instances where the organization allows the user to install approved software packages, such as from an approved software repository. The operating system or software configuration management utility must enforce control of software installation by users based upon what types of software installations are permitted (e.g., updates and security patches to existing software) and what types of installations are prohibited (e.g., software whose pedigree with regard to being potentially malicious is unknown or suspect) by the organization.
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if the system is configured to prohibit user installation of software, first check to ensure the Parental Controls are enabled with the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep -A 5 familyControlsEnabled | grep “/Users" If the result is null, or does not contain “/Users/“, this is a finding