Apple macOS 11 (Big Sur) Security Technical Implementation Guide
| Version 1 Release 1 |
| 2020-11-20 |
| U_Apple_macOS_11_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 (105)
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" allowAutoUnlock = 0; If there is no result or "allowAutoUnlock" is not set to "0", 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 "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 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 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 idleTime If there is no result, or if "idleTime" is not set to "900" seconds or less, 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 setting is enforced using the "Smart Card Policy" configuration profile. Note: Before applying the "Smart Card Policy", the supplemental guidance provided with the STIG should be consulted to ensure continued access to the operating system.
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 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 modulePath If there is no result or defined "modulePath", 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.
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 with Wi-Fi support software disabled.
Discussion
Allowing devices and users to connect to or from the system without first authenticating them allows untrusted access and can lead to a compromise or attack. Since wireless communications can be intercepted, it is necessary to use encryption to protect the confidentiality of information in transit. Wireless technologies include, for example, microwave, packet radio (UHF/VHF), 802.11x, and Bluetooth. Wireless networks use authentication protocols (e.g., EAP/TLS, PEAP), which provide credential protection and mutual authentication. Satisfies: SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000379-GPOS-00164
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 disable the SSHD service.
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. Privileged access contains control and configuration information and is particularly sensitive, so additional protections are necessary. This is maintained by using cryptographic mechanisms, such as a hash function or digital signature, to protect integrity. Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the Internet) or an internal network. 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. The implementation of OpenSSH that is included with macOS does not utilize a FIPS 140-2 validated cryptographic module. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000033-GPOS-00014, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000112-GPOS-00057, SRG-OS-000113-GPOS-00058, SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190
Fix Text
Disable the "SSHD" service by using the following command: usr/bin/sudo /bin/launchctl disable system/com.openssh.sshd The system may need to be restarted for the update to take effect.
Check Content
Verify the "SSHD" service is disabled by using the following command: /bin/launchctl print-disabled system | grep sshd If the results do not show "com.openssh.sshd => true", this is a finding.
The macOS system must automatically remove or disable temporary and emergency 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. 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 may be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements. Satisfies: SRG-OS-000002-GPOS-00002, SRG-OS-000123-GPOS-00064
Fix Text
This setting may be enforced using local policy or by a directory service. To set local policy to disable a temporary or emergency user, create a plain text file containing the following: <dict> <key>policyCategoryAuthentication</key> <array> <dict> <key>policyContent</key> <string>policyAttributeCurrentTime < policyAttributeCreationTime+259299</string> <key>policyIdentifier</key> <string>Disable Tmp Accounts </string> </dict> </array> </dict> 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" and the path to the file in place of "/path/to/file". /usr/bin/sudo /usr/bin/pwpolicy -u username setaccountpolicies /path/to/file
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. If there are no temporary or emergency accounts defined on the system, this is Not Applicable. To check if the password policy is configured to disable a temporary or emergency 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, 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
Fix Text
To enable the TIMED service, run the following command: /usr/bin/sudo systemsetup -setusingnetworktime on To configure a time server, use the following command: /usr/bin/sudo systemsetup -setnetworktimeserver "server"
Check Content
The TIMED (NTP replacement in Big Sur) service must be enabled on all networked systems. To check if the service is running, use the following command: sudo systemsetup -getusingnetworktime If the following in not returned, this is a finding: Network Time: On To verify that an authorized Time Server is configured, run the following command: sudo systemsetup -getnetworktimeserver 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 utilize an HBSS solution and implement all DoD required modules.
Discussion
The macOS system must employ automated mechanisms to determine the state of system components. The DoD requires the installation and use of an approved HBSS solution to be implemented on the operating system. For additional information, reference all applicable HBSS OPORDs and FRAGOs on SIPRNET.
Fix Text
Install an approved HBSS solution onto the system and ensure that all components are at least updated to their DoD approved minimal versions.
Check Content
Verify that there is an approved HBSS solution installed on the system. If there is not an approved HBSS solution installed, this is a finding. Verify that all installed components of the HBSS Solution are at the DoD approved minimal version. If the installed components are not at the DoD approved minimal versions, 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
If the system is using a mandatory Smart Card Policy, this is Not Applicable. To determine if the system is integrated to a directory service, run the following command: /usr/bin/dscl localhost -list . | /usr/bin/grep "Active Directory" If no results are returned, 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.
Fix Text
This setting may be enforced using the "Passcode Policy" configuration profile or by a directory service.
Check Content
Password policy is set with the Passcode Policy configuration profile. /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.
The macOS system must display the Standard Mandatory DoD Notice and Consent Banner before granting remote 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 run the following command: # /usr/bin/sudo /usr/bin/sed -i.bak 's/^#Banner.*/Banner \/etc\/banner/' /etc/ssh/sshd_config
Check Content
If SSH is not being used, this is Not Applicable. 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 Banner /etc/banner 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 GUI 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
Fix Text
Create an RTF file containing the required text. Name the file "PolicyBanner.rtf" or "PolicyBanner.rtfd" and place it in "/Library/Security/".
Check Content
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 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 normal 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. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000206-GPOS-00084
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 normal 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 be configured with dedicated user accounts to decrypt the hard disk upon startup.
Discussion
When "FileVault" and Multifactor Authentication are configured on the operating system, a dedicated user must be configured to ensure that the implemented Multifactor Authentication rules are enforced. If a dedicated user is not configured to decrypt the hard disk upon startup, the system will allow a user to bypass Multifactor Authentication rules during initial startup and first login.
Fix Text
Create an authorized user account that will be used to unlock the disk on startup. Disable the login ability of the newly created user account: # sudo dscl . append /Users/<FileVault_User> AuthenticationAuthority DisabledUser Remove all FileVault login access from each user account defined on the system that is not a designated FileVault user: # sudo fdesetup remove -user <username>
Check Content
Retrieve a list of authorized FileVault users: # sudo fdesetup list fvuser,85F41F44-22B3-6CB7-85A1-BCC2EA2B887A If any unauthorized users are listed, this is a finding. Verify that the authorized FileVault users are marked as “DisabledUser”, preventing console logins: Note: This procedure will need to be run for each authorized FileVault User. # sudo dscl . read /Users/<FileVault_User> AuthenticationAuthority | grep "DisabledUser" AuthenticationAuthority: ;ShadowHash;HASHLIST:<SALTED-SHA512-PBKDF2,SRP-RFC5054-4096-SHA512-PBKDF2> ;Kerberosv5;;unlock@LKDC:SHA1.20BABA05A6B1A86A8C57581A8487596640A3E37B;LKDC:SHA1.20CEBE04A5B1D92D8C58189D8487593350D3A40A; ;SecureToken; DisabledUser If the FileVault user is not disabled, this is a finding.
The macOS system must be configured to disable password forwarding for FileVault2.
Discussion
When "FileVault" and Multifactor Authentication are configured on the operating system, a dedicated user must be configured to ensure that the implemented Multifactor Authentication rules are enforced. If a dedicated user is not configured to decrypt the hard disk upon startup, the system will allow a user to bypass Multifactor Authentication rules during initial startup and first login.
Fix Text
This setting is enforced using the "Login Window Policy" configuration profile.
Check Content
Verify that password forwarding has been disabled on the system: # /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep "DisableFDEAutoLogin" DisableFDEAutologin = 1; If "DisableFDEAutologin" is not set to a value of "1", this is a finding.
The macOS system must be configured with the SSH daemon ClientAliveInterval option set to 900 or less.
Discussion
If SSH is not being used, this is Not Applicable. The SSH daemon "ClientAliveInterval" option must be set correctly. To check the idle timeout setting for SSH sessions, run the following: /usr/bin/grep ^ClientAliveInterval /etc/ssh/sshd_config If the setting is not "900" or less, this is a finding.
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/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
If SSH is not being used, this is Not Applicable. 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/grep ^ClientAliveCountMax /etc/ssh/sshd_config If the setting is not "ClientAliveCountMax 0", this is a finding.
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/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
If SSH is not being used, this is Not Applicable. 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/grep ^LoginGraceTime /etc/ssh/sshd_config If the value is not set to "30" or less, this is a finding.
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/grep ^LoginGraceTime /etc/ssh/sshd_config If the value is not set to "30" or less, this is a finding.
The macOS system must implement approved ciphers to protect the confidentiality of SSH connections.
Discussion
Unapproved mechanisms for authentication to the cryptographic module are not verified, and therefore cannot be relied upon to provide confidentiality or integrity, resulting in the compromise of DoD data. Operating systems using encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. The implementation of OpenSSH that is included with macOS does not use a FIPS 140-2 validated cryptographic module. While the listed ciphers are FIPS 140-2 approved algorithms, the module implementing them has not been validated. By specifying a cipher list with the order of ciphers being in a “strongest to weakest” orientation, the system will automatically attempt to use the strongest cipher for securing SSH connections. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174
Fix Text
Configure SSH to use secure cryptographic algorithms. To ensure that "Ciphers" set correctly, run the following command: /usr/bin/sudo /usr/bin/grep -q '^Ciphers' /etc/ssh/sshd_config && /usr/bin/sudo /usr/bin/sed -i.bak 's/^Ciphers.*/Ciphers aes256-ctr,aes192-ctr,aes128-ctr/' /etc/ssh/sshd_config || /usr/bin/sudo /usr/bin/sed -i.bak '/.*Ciphers and keying.*/a\'$'\n''Ciphers aes256-ctr,aes192-ctr,aes128-ctr'$'\n' /etc/ssh/sshd_config The SSH service must be restarted for changes to take effect.
Check Content
If SSH is not being used, this is Not Applicable. Inspect the "Ciphers" configuration with the following command: Note: The location of the "sshd_config" file may vary if a different daemon is in use. # /usr/bin/grep "^Ciphers" /etc/ssh/sshd_config Ciphers aes256-ctr,aes192-ctr,aes128-ctr If any ciphers other than "aes256-ctr", "aes192-ctr", or "aes128-ctr" are listed, the order differs from the example above, or the "Ciphers" keyword is missing, this is a finding.
The macOS system must use only Message Authentication Codes (MACs) employing FIPS 140-2 validated cryptographic hash algorithms.
Discussion
Unapproved mechanisms for authentication to the cryptographic module are not verified, and therefore cannot be relied upon to provide confidentiality or integrity, resulting in the compromise of DoD data. Operating systems using encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. The implementation of OpenSSH that is included with macOS does not use a FIPS 140-2 validated cryptographic module. While the listed MACs are FIPS 140-2 approved algorithms, the module implementing them has not been validated. By specifying a Keyed-Hash Message Authentication Code list with the order of hashes being in a “strongest to weakest” orientation, the system will automatically attempt to use the strongest hash for securing SSH connections. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174
Fix Text
Configure SSH to use secure Keyed-Hash Message Authentication Codes. To ensure that "MACs" set correctly, run the following command: /usr/bin/sudo /usr/bin/grep -q '^MACs' /etc/ssh/sshd_config && /usr/bin/sudo /usr/bin/sed -i.bak 's/^MACs.*/MACs hmac-sha2-256,hmac-sha2-512/' /etc/ssh/sshd_config || /usr/bin/sudo /usr/bin/sed -i.bak '/.*Ciphers and keying.*/a\'$'\n''MACs hmac-sha2-512,hmac-sha2-256'$'\n' /etc/ssh/sshd_config The SSH service must be restarted for changes to take effect.
Check Content
If SSH is not being used, this is Not Applicable. Inspect the "MACs" configuration with the following command: Note: The location of the "sshd_config" file may vary if a different daemon is in use. /usr/bin/grep "^Macs" /etc/ssh/sshd_config MACs hmac-sha2-512,hmac-sha2-256 If any hashes other than "hmac-sha2-512" and/or "hmac-sha2-256" are listed, the order differs from the example above, or the "MACs" keyword is missing, this is a finding.
The macOS system must implement an approved Key Exchange Algorithm.
Discussion
Unapproved mechanisms for authentication to the cryptographic module are not verified, and therefore cannot be relied upon to provide confidentiality or integrity, resulting in the compromise of DoD data. Operating systems using encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. The implementation of OpenSSH that is included with macOS does not utilize a FIPS 140-2 validated cryptographic module. While the listed Key Exchange Algorithms are FIPS 140-2 approved, the module implementing them has not been validated. By specifying a Key Exchange Algorithm list with the order of hashes being in a “strongest to weakest” orientation, the system will automatically attempt to use the strongest Key Exchange Algorithm for securing SSH connections. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174
Fix Text
Configure SSH to use a secure Key Exchange Algorithm. To ensure that "KexAlgorithms" set correctly, run the following command: /usr/bin/sudo /usr/bin/grep -q '^KexAlgorithms' /etc/ssh/sshd_config && /usr/bin/sudo /usr/bin/sed -i.bak 's/^KexAlgorithms.*/KexAlgorithms diffie-hellman-group-exchange-sha256/' /etc/ssh/sshd_config || /usr/bin/sudo /usr/bin/sed -i.bak '/.*Ciphers and keying.*/a\'$'\n''KexAlgorithms diffie-hellman-group-exchange-sha256'$'\n' /etc/ssh/sshd_config The SSH service must be restarted for changes to take effect.
Check Content
If SSH is not being used, this is Not Applicable. Inspect the "KexAlgorithms" configuration with the following command: Note: The location of the "sshd_config" file may vary if a different daemon is in use. /usr/bin/grep "^KexAlgorithms" /etc/ssh/sshd_config KexAlgorithms diffie-hellman-group-exchange-sha256 If any algorithm other than "diffie-hellman-group-exchange-sha256" is listed or the "KexAlgorithms" keyword is missing, 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). If events associated with nonlocal administrative access or diagnostic sessions are not logged, a major tool for assessing and investigating attacks would not be available. This requirement addresses auditing-related issues associated with maintenance tools used specifically for diagnostic and repair actions on organizational information systems. Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the internet) or an internal network. Local maintenance and diagnostic activities are those activities carried out by individuals physically present at the information system or information system component and not communicating across a network connection. This requirement applies to hardware/software diagnostic test equipment or tools. This requirement does not cover hardware/software components that may support information system maintenance, yet are a part of the system, for example, the software implementing "ping," "ls," "ipconfig," or the hardware and software implementing the monitoring port of an Ethernet switch. 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 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. 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-000032-GPOS-00013, 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 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), 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-000303-GPOS-00120, SRG-OS-000337-GPOS-00129, SRG-OS-000358-GPOS-00145, SRG-OS-000359-GPOS-00146
Fix Text
To enable the audit service, run the following command: /usr/bin/sudo /bin/launchctl enable system/com.apple.auditd The system may need to be restarted for the update to take effect.
Check Content
To check if the audit service is running, use the following command: launchctl print-disabled system| grep auditd If the return is not: "com.apple.auditd" => false" the audit service is disabled, and 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
Verify that the audit control system is configured to shut down upon failure using 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 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 normal 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.
Check Content
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 normal 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]
Check Content
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 normal 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 normal 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 normal 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 normal 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 $2}') The results should show the permissions (first column) to be "700" or less permissive. If they do not, this is a finding.
The macOS system must audit the enforcement actions used to restrict access associated with changes to the system.
Discussion
By auditing access restriction enforcement, changes to application and OS configuration files can be audited. Without auditing the enforcement of access restrictions, it will be difficult to identify attempted attacks and an audit trail will not be available for forensic investigation. Enforcement actions are the methods or mechanisms used to prevent unauthorized changes to configuration settings. Enforcement action methods may be as simple as denying access to a file based on the application of file permissions (access restriction). Audit items may consist of lists of actions blocked by access restrictions or changes identified after the fact. Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000064-GPOS-00033, SRG-OS-000365-GPOS-00152, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-OS-000474-GPOS-00219
Fix Text
To set the audit flags to the recommended setting, run the following command to add the flags "fm", "-fr", "-fw", and "-fd" all at once: /usr/bin/sudo /usr/bin/sed -i.bak '/^flags/ s/$/,fm,-fr,-fw,-fd/' /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, and -fd, which audits failed file deletion. If "fm", "-fr", "-fw", and "-fd" are not listed in the result of the check, this is a finding.
The macOS system must allocate audit record storage capacity to store at least one week's 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.
Check Content
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".
Check Content
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
Check Content
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 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
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/$/,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.
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 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 accept and verify Personal Identity Verification (PIV) credentials, implement a local cache of revocation data to support path discovery and validation in case of the inability to access revocation information via the network, and only allow the use of DoD PKI-established certificate authorities to verify the establishment of protected sessions.
Discussion
The use of PIV credentials facilitates standardization and reduces the risk of unauthorized access. Without configuring a local cache of revocation data, there is the potential to allow access to users who are no longer authorized (users with revoked certificates). Untrusted Certificate Authorities (CA) can issue certificates, but they may be issued by organizations or individuals that seek to compromise DoD systems or by organizations with insufficient security controls. If the CA used for verifying the certificate is not a DoD-approved CA, trust of this CA has not been established. DoD has mandated the use of the CAC to support identity management and personal authentication for systems covered under Homeland Security Presidential Directive (HSPD) 12, as well as making the CAC a primary component of layered protection for national security systems. The DoD will only accept PKI-certificates obtained from a DoD-approved internal or external certificate authority. Reliance on CAs for the establishment of secure sessions includes, for example, the use of SSL/TLS certificates. Satisfies: SRG-OS-000376-GPOS-00161, SRG-OS-000377-GPOS-00162, SRG-OS-000384-GPOS-00167, SRG-OS-000403-GPOS-00182, SRG-OS-000067-GPOS-00035
Fix Text
This setting is enforced using the "Smart Card Policy" configuration profile. Note: Before applying the "Smart Card Policy", the supplemental guidance provided with the STIG should be consulted to ensure continued access to the operating system.
Check Content
To verify that certificate checks are occurring, run the following command. /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep checkCertificateTrust If the output is null or the value returned, "checkCertificateTrust = 1", is not equal to (1) or greater, this is a finding.
The macOS system must require individuals to be authenticated with an individual authenticator prior to using a group authenticator.
Discussion
Administrator users 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
If SSH is not being used, this is Not Applicable. To check if SSH has root logins enabled, run the following command: /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 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: /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 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: /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 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
Disable the Location Services: The setting is found in System Preferences >> Security & Privacy >> Privacy >> Location Services. Uncheck the box labeled "Enable Location Services".
Check Content
If Location Services are authorized by the Authorizing Official, this is Not Applicable. Verify that Location Services are disabled: 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.
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
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
To check that Bonjour broadcasts have been disabled, use the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep NoMulticastAdvertisements If the return is not, "NoMulticastAdvertisments = 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: /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 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 is non-essential and must be disabled.
Fix Text
This setting is enforced using the "Custom Policy" configuration profile.
Check Content
To check if Internet Sharing is disabled, use the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep forceInternetSharingOff If the return is not, "forceInternetSharingOff = 1", this is a finding.
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: /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 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. Note: There is a known bug in the graphical user interface where the user can toggle AirDrop in the UI, which indicates the service has been turned on, but it remains disabled if the Restrictions Profile has been applied.
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
Verify that AirDrop has been disabled by running the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowAirDrop If the return is not, "allowAirDrop = 0", 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 return 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 return 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 Calendar application's connections to Apple's iCloud 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 iCloudCalendar is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudCalendar If the return 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 Reminder application's connections to Apple's iCloud 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 iCloud Reminders is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudReminders If the return 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 Address Book(Contacts) application's connections to Apple's iCloud 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
Verify that the operating system is configured to disable iCloud Address Book services using 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 Mail iCloud 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 Mail application's connections to Apple's iCloud 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 Mail iCloud 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 Notes application's connections to Apple's iCloud 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 iCloud Notes is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCloudNotes If the return is not “allowCloudNotes = 0”, this is a finding.
The macOS system must cover or disable the built-in or attached camera when not in use.
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. Failing to disconnect from collaborative computing devices (i.e., cameras) can result in subsequent compromises of organizational information. Providing easy methods to physically disconnect from such devices after a collaborative computing session helps to ensure that participants actually carry out the disconnect activity without having to go through complex and tedious procedures. 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
If the device or operating system does not have a camera installed, this requirement is not applicable. This requirement is not applicable to mobile devices (smartphones and tablets), where the use of the camera is a local AO decision. This requirement is not applicable to dedicated VTC suites located in approved VTC locations that are centrally managed. For an external camera, if there is not a method for the operator to manually disconnect camera at the end of collaborative computing sessions, this is a finding. For a built-in camera, the camera must be protected by a camera cover (e.g., laptop camera cover slide) when not in use. If the built-in camera is not protected with a camera cover, or is not physically disabled, this is a finding. If the camera is not disconnected, covered, or physically disabled, the following configuration is required: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep allowCamera If the result is “allowCamera = 1” and the collaborative computing device has not been authorized for use, this is a finding.
The macOS system must be configured to disable the application Mail.
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.
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 "Mail" If the return does not contain "/System/Applications/Mail.app/Contents/MacOS/Mail", 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. 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 "Assistant Allowed" -e "Ironwood Allowed" If the output is not: “Assistant Allowed = 0” “Ironwood Allowed = 0”, this is a finding.
The macOS system must be configured to disable sending diagnostic and usage data to Apple.
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 ability to submit diagnostic data to Apple must be disabled.
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile. The setting "Send diagnostic & usage data to Apple" can also be configured in System Preferences >> Security & Privacy >> Privacy >> Analytics & Improvement. Uncheck the box that says, "Share Mac Analytics". Uncheck the box that says, "Improve Siri & Dictation". Uncheck the box that says, "Share with App Developers".
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 >> Analytics & Improvement. If the box that says, "Send diagnostic & usage data to Apple" is checked, this is a finding. If the box that says, "Improve Siri & Dictation" is checked, this is a finding. If the box that says, "Share with App Developers" is checked, 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: /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 to disable the application Calendar.
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.
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 "Calendar" If the return does not contain "/System/Applications/Calendar.app/Contents/MacOS/Calendar", 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 iCloud System Preference Pane must be disabled.
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 6 DisabledPreferencePanes If the return is not an array which contains: “com.apple.preferences.AppleIDPrefPane”, 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 Internet Accounts System Preference Pane must be disabled. Satisfies: SRG-OS-000370-GPOS-00155, SRG-OS-000095-GPOS-00049
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 6 DisabledPreferencePanes If the return is not an array which contains: "com.apple.preferences.internetaccounts", this is a finding.
The macOS system must be configured to disable the Cloud Setup 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 which cannot be disabled.
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if CloudSetup is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep SkipCloudSetup If the return is not "SkipCloudSetup = 1", this is a finding.
The macOS system must be configured to disable the Privacy Setup 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 which cannot be disabled.
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if PrivacySetup is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep SkipPrivacySetup If the return is not “SkipPrivacySetup = 1”, this is a finding.
The macOS system must be configured to disable the Cloud Storage Setup 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 which cannot be disabled.
Fix Text
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
To check if CloudStorage Setup is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep SkipiCloudStorageSetup If the return is not “SkipiCloudStorageSetup = 1”, this is a finding.
Apple macOS must be configured to disable the tftp service.
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: /usr/bin/sudo /bin/launchctl disable system/com.apple.tftpd
Check Content
To check if the tfptd service is disabled, run the following command: sudo launchctl print-disabled system | grep tftpd If the results do not show the following, this is a finding: "com.apple.tftpd" => true
The macOS system must be configured to disable the Siri Setup 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 Siri setup pop-up 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 SiriSetup is disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep SkipSiriSetup If the return is not "SkipSiriSetup = 1", this is a finding.
The macOS system must disable iCloud Keychain synchronization.
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. Keychain synchronization 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 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
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. iCloud document synchronization 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 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
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. iCloud Bookmark syncing 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 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
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. iCloud Photo Library 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 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 the Screen Sharing feature.
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 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 "RestrictionsPolicy" 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 normal users from overriding its setting. If 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 "RestrictionsPolicy" 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 DisableOverride If the return is null, or is not: DisableOverride = 1; This is a finding.
The macOS system must be configured with Bluetooth turned off unless approved by the organization.
Discussion
Without protection of communications with wireless peripherals, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read, altered, or used to compromise the operating system. This requirement applies to wireless peripheral technologies (e.g., wireless mice, keyboards, displays, etc.) used with an operating system. Wireless peripherals (e.g., Wi-Fi/Bluetooth/IR keyboards, mice, and pointing devices and Near Field Communications [NFC]) present a unique challenge by creating an open, unsecured port on a computer. Wireless peripherals must meet DoD requirements for wireless data transmission and be approved for use by the AO. Even though some wireless peripherals, such as mice and pointing devices, do not ordinarily carry information that need to be protected, modification of communications with these wireless peripherals may be used to compromise the operating system. Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of communications with wireless peripherals can be accomplished by physical means (e.g., employing physical barriers to wireless radio frequencies) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. If the wireless peripheral is only passing telemetry data, encryption of the data may not be required.
Fix Text
This setting is enforced using the "Custom 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 enforce access restrictions.
Discussion
Failure to provide logical access restrictions associated with changes to system configuration may have significant effects on the overall security of the system. When dealing with access restrictions pertaining to change control, it should be noted that any changes to the hardware, software, and/or firmware components of the operating system can have significant effects on the overall security of the system. Accordingly, only qualified and authorized individuals should be allowed to obtain access to operating system components for the purposes of initiating changes, including upgrades and modifications. Logical access restrictions include, for example, controls that restrict access to workflow automation, media libraries, abstract layers (e.g., changes implemented into third-party interfaces rather than directly into information systems), and change windows (e.g., changes occur only during specified times, making unauthorized changes easy to discover).
Fix Text
This setting is enforced using the "Login Window Policy" configuration profile.
Check Content
To check that the system is configured to disable the guest account, run the following command: # /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep DisableGuestAccount If the result is null or not "DisableGuestAccount = 1", 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/sbin/spctl --status | /usr/bin/grep enabled If "assessments enabled" is not returned, this is a finding.
The macOS system must not allow an unattended or automatic logon to the system.
Discussion
Failure to restrict system access to authenticated users negatively impacts operating system security.
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 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 6 familyControlsEnabled | grep "/Users" If the result is null, or does not contain "/Users/", this is a finding.
The macOS system must set permissions on user home directories to prevent users from having access to read or modify another user's files.
Discussion
Configuring the operating system to use the most restrictive permissions possible for user home directories helps to protect against inadvertent disclosures. Satisfies: SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00230
Fix Text
To ensure the appropriate permissions are set for each user on the system, run the following command: diskutil resetUserPermissions / userid, where userid is the user name for the user whose home directory permissions need to be repaired.
Check Content
To verify that permissions are set correctly on user home directories, use the following commands: ls -le /Users Should return a listing of the permissions of the root of every user account configured on the system. For each of the users, the permissions should be: "drwxr-xr-x+" with the user listed as the owner and the group listed as "staff". The plus(+) sign indicates an associated Access Control List, which should be: 0: group:everyone deny delete For every authorized user account, also run the following command: /usr/bin/sudo ls -le /Users/userid, where userid is an existing user. This command will return the permissions of all of the objects under the users' home directory. The permissions for each of the subdirectories should be: drwx------+ 0: group:everyone deny delete With the exception of the "Public" directory, whose permissions should match the following: drwxr-xr-x+ 0: group:everyone deny delete If the permissions returned by either of these checks differ from what is shown, this is a finding.
The macOS system must authenticate peripherals before establishing a connection.
Discussion
Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. Peripherals include, but are not limited to, such devices as flash drives, external storage, and printers.
Fix Text
To ensure that authentication is required to access all system level preference panes use the following procedure: Copy the authorization database to a file using the following command: /usr/bin/sudo /usr/bin/security authorizationdb read system.preferences > ~/Desktop/authdb.txt edit the file to change: <key>shared</key> <true/> To read: <key>shared</key> <false/> Reload the authorization database with the following command: /usr/bin/sudo /usr/bin/security authorizationdb write system.preferences < ~/Desktop/authdb.txt
Check Content
To check that macOS is configured to require authentication to all system preference panes, use the following commands: /usr/bin/sudo /usr/bin/security authorizationdb read system.preferences | grep -A1 shared If what is returned does not include the following, this is a finding. <key>shared</key> <false/>
The macOS system must use an approved 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 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. Use of weak or untested encryption algorithms undermines the purposes of utilizing 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-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 contains unapproved certificates, 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 is enforced using the "Passcode Policy" configuration profile.
Check Content
To check the currently applied policies for passwords and accounts, use the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep requireAlphanumeric If the return is not “requireAlphanumeric = 1”, 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 is enforced using the "Passcode Policy" configuration profile.
Check Content
To check the currently applied policies for passwords and accounts, use the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep maxPINAgeInDays If "maxPINAgeInDays" is set a value greater than "60", 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 is enforced using the "Passcode Policy" configuration profile.
Check Content
To check the currently applied policies for passwords and accounts, use the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep pinHistory If the return is not “pinHistory = 5” or greater, 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.
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 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 be configured to prevent displaying password hints.
Discussion
Password hints leak information about passwords in use and can lead to loss of confidentiality.
Fix Text
This setting is enforce using the "Login Window" Policy.
Check Content
To check that password hints are disabled, run the following command: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep RetriesUntilHint If the return is null or is not "RetriesUntilHint = 0", this is a finding.
Apple macOS must be configured with a firmware password to prevent access to single user mode and booting from alternative media.
Discussion
Single user mode and the boot picker, as well as numerous other tools are available on macOS through booting while holding the "Option" key down. Setting a firmware password restricts access to these tools.
Fix Text
To set a firmware passcode use the following command. sudo /usr/sbin/firmwarepasswd -setpasswd Note: If firmware password or passcode is forgotten, the only way to reset the forgotten password is through the use of a machine specific binary generated and provided by Apple. Schedule a support call, and provide proof of purchase before the firmware binary will be generated.
Check Content
To ensure that a firmware password is set, run the following command: # sudo /usr/sbin/firmwarepasswd -check If the return is not "Password Enabled: Yes", this is a finding.
The macOS system must use multifactor authentication for local access to privileged and non-privileged accounts.
Discussion
Without the use of multifactor authentication, the ease of access to privileged and non-privileged functions is greatly increased. Multifactor authentication requires using two or more factors to achieve authentication. Factors include: 1) something a user knows (e.g., password/PIN); 2) something a user has (e.g., cryptographic identification device, token); and 3) something a user is (e.g., biometric). A privileged account is defined as an information system account with authorizations of a privileged user. Local access is defined as access to an organizational information system by a user (or process acting on behalf of a user) communicating through a direct connection without the use of a network. The DoD CAC with DoD-approved PKI is an example of multifactor authentication. Satisfies: SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055, SRG-OS-000068-GPOS-00036
Fix Text
This setting is enforced using the "Smart Card Policy" configuration profile. Note: Before applying the "Smart Card Policy", the supplemental guidance provided with the STIG must be consulted to ensure continued access to the operating system.
Check Content
To verify that the system is configured to enforce multi-factor authentication, run the following commands: /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep enforceSmartCard If the results do not show "enforceSmartCard=1", this is a finding. .
The macOS system must be configured so that the login command requires smart card authentication.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix Text
Make a backup of the PAM LOGIN settings using the following command: sudo cp /etc/pam.d/login /etc/pam.d/login_backup_`date "+%Y-%m-%d_%H:%M"` Replace the contents of "/etc/pam.d/login" with the following: # login: auth account password session auth sufficient pam_smartcard.so auth optional pam_krb5.so use_kcminit auth optional pam_ntlm.so try_first_pass auth optional pam_mount.so try_first_pass auth required pam_opendirectory.so try_first_pass auth required pam_deny.so account required pam_nologin.so account required pam_opendirectory.so password required pam_opendirectory.so session required pam_launchd.so session required pam_uwtmp.so session optional pam_mount.so
Check Content
For systems that are not utilizing smart card authentication, this is Not Applicable. To verify that the "login" command has been configured to require smart card authentication, run the following command: # cat /etc/pam.d/login | grep -i pam_smartcard.so If the text that returns does not include the line, "auth sufficient pam_smartcard.so" at the TOP of the listing, this is a finding.
The macOS system must be configured so that the su command requires smart card authentication.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix Text
Make a backup of the PAM SU settings using the following command: cp /etc/pam.d/su /etc/pam.d/su_backup_`date "+%Y-%m-%d_%H:%M"` Replace the contents of "/etc/pam.d/su" with the following: # su: auth account password session auth sufficient pam_smartcard.so auth required pam_rootok.so auth required pam_group.so no_warn group=admin,wheel ruser root_only fail_safe account required pam_permit.so account required pam_opendirectory.so no_check_shell password required pam_opendirectory.so session required pam_launchd.so
Check Content
For systems that are not utilizing smart card authentication, this is Not Applicable. To verify that the "su" command has been configured to require smart card authentication, run the following command: cat /etc/pam.d/su | grep -i pam_smartcard.so If the text that returns does not include the line, "auth sufficient pam_smartcard.so" at the TOP of the listing, this is a finding.
The macOS system must be configured so that the sudo command requires smart card authentication.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix Text
Make a backup of the PAM SUDO settings using the following command: cp /etc/pam.d/login /etc/pam.d/sudo_backup_`date "+%Y-%m-%d_%H:%M"` Replace the contents of "/etc/pam.d/sudo" with the following: # sudo: auth account password session auth sufficient pam_smartcard.so #auth required pam_opendirectory.so auth required pam_deny.so account required pam_permit.so password required pam_deny.so session required pam_permit.so
Check Content
For systems that are not utilizing smart card authentication, this is Not Applicable. To verify that the "sudo" command has been configured to require smart card authentication, run the following command: cat /etc/pam.d/sudo | grep -i pam_smartcard.so If the text that returns does not include the line, "auth sufficient pam_smartcard.so" at the TOP of the listing, 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
Some system log files are controlled by "newsyslog" and "aslmanager". The following commands check for log files that exist on the system and print the path to the log with the 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 Each command may return zero or more files. 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
The following commands check for log files that exist on the system and print the path to the log with the 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 Each command may return zero or more files. If the permissions on log files are not "640" or less permissive, this is a finding.
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 system must enable System Integrity Protection.
Discussion
System Integrity Protection (SIP) is vital to the protection of the integrity of macOS. SIP restricts what actions can be performed by administrative users, including root, against protected parts of the operating system. SIP protects all system binaries, including audit tools, from unauthorized access by preventing the modification or deletion of system binaries, or the changing of the permissions associated with those binaries. SIP limits the privileges to change software resident within software libraries to processes that have signed by Apple and have special entitlements to write to system files, such as Apple software updates and Apple installers. By protecting audit binaries, SIP ensures the presence of an audit record generation capability for DoD-defined auditable events for all operating system components and supports on-demand and after-the-fact reporting requirements. Satisfies: SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000062-GPOS-00031, SRG-OS-000122-GPOS-00063, 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
Fix Text
To re-enable "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
Check Content
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 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
Verify that "FileVault 2" is enabled by running the following command: /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 Application Firewall must be enabled.
Discussion
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
This setting is enforced using the "Restrictions Policy" configuration profile.
Check Content
Verify that the built-in Firewall is enabled: # /usr/sbin/system_profiler SPConfigurationProfileDataType | /usr/bin/grep 'EnableFirewall\|EnableStealthMode' If the return is not "EnableFirewall = 1;" and "EnableStealthMode = 1;" this is a finding.