Free DISA STIG and SRG Library | Vaulted

Exchange 2010 Mailbox Server STIG

Version 1 Release 9
2017-01-27
U_Exchange_2010_Mailbox_V1R9_Manual-xccdf.xml
The Microsoft Exchange Server 2010 STIGs cover four of the five roles available with Microsoft Exchange Server 2010. The Email Services Policy STIG must also be reviewed for each site hosting email services. Also, for the Client Access server, the IIS guidance must be reviewed prior to the OWA checks. Comments or proposed revisions to this document should be sent via e-mail to the following address: disa.stig_spt@mail.mil.

Vulnerabilities (33)

Public Store storage quota must be limited.

Finding ID
Exch-1-106
Rule ID
SV-43993r1_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-106
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

This setting controls the maximum sizes of a Public Folder and the system’s response if these limits are exceeded. There are two available controls and the system response when the quota has been exceeded. The first control sends an email warning to Folder Owners roles alerting them that the folder has exceeded its quota. The second level prevents posting any additional items to the folder. As a practical matter, level 1 serves the purpose of prompting owners to manage their folders. Level 2 impedes users in their ability to work, and is not required where folder use interruption is not acceptable. Public Folder Storage Quota Limitations are not a substitute for overall disk space monitoring.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-PublicFolderDatabase <'publicdatabasename'> -ProhibitPostQuota <'SitesProhibitPostQuotaLimit'>

Check Content

If public folders are not used this check is NA. Obtain the Email Domain Security Plan (EDSP) and locate the value for 'ProhibitPostQuota'. Open the Exchange Management Shell and enter the following command: Get-PublicFolderDatabase | Select Name, Identity, ProhibitPostQuota If the value of 'ProhibitPostQuota' is not set to the sites 'ProhibitPostQuota', this is a finding.

IA Controls

ECSC-1

The Public Folder Stores must mount at startup.

Finding ID
Exch-1-109
Rule ID
SV-43997r1_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-109
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Administrator responsibilities include the ability to react to unplanned maintenance tasks or emergency situations that may require Public Folder Store data manipulation. Occasionally, there may be a need to start the server with 'unmounted' data stores, if manual maintenance is being performed on them. Failure to uncheck the 'do not mount on startup' condition will result in unavailability of Public Folder services. Correct configuration of this control will prevent unplanned outages due to being enabled. On occasions when it is needed, care should be taken in process steps to clear the checkbox task completion, so that public folder stores are available to users (unmounted public folder stores are not available to users).

Fix Text

Open the Exchange Management Shell and enter the following command: Set-PublicFolderDatabase -Identity <'PublicFolderName'> -MountAtStartup $true

Check Content

If public folders are not used this check is NA. Open the Exchange Management Shell and enter the following command: Get-PublicFolderDatabase | Select Name, Identity, MountAtStartup If the value of 'MountAtStartup' is not set to 'True', this is a finding.

IA Controls

ECSC-1

Public Folder stores must be retained until backups are complete.

Finding ID
Exch-1-112
Rule ID
SV-44000r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-1-112
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Backup and recovery procedures are an important part of overall system availability and integrity. Complete backups reduce the chance of accidental deletion of important information, and make it possible to have complete recoveries. It is not uncommon for users to receive and delete documents in the scope of a single backup cycle. This setting ensures at least one backup has been run on the folder store before the message physically disappears. By enabling this setting, all messages written to recipients who have accounts on this store will reside in backups even if they have been deleted by the user before the backup has run.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-PublicFolderDatabase <'PublicFolderDatabaseName'> -RetainDeletedItemsUntilBackup $true

Check Content

If public folders are not used this check is NA. Open the Exchange Management Shell and enter the following command: Get-PublicFolderDatabase| Select Name, Identity, RetainDeletedItemsUntilBackup If the value of 'RetainDeletedItemsUntilBackup' is not set to 'True', this is a finding.

IA Controls

ECSC-1

Public Folder database must not be overwritten by a restore.

Finding ID
Exch-1-115
Rule ID
SV-44002r1_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-115
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Email system availability depends in part on best practices strategies for setting tuning configurations. Unauthorized or accidental restoration of public folder data risks data loss or corruption. This setting controls whether the public folder store can be overwritten by a restore from backup, which will cause loss of all information added after the backup was created. It should only be enabled during maintenance windows or following an outage (immediately before a restore is to be made), and cleared again immediately afterwards. During production windows, this feature must be disabled.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-PublicFolderDatabase <'PublicFolderDatabaseName'> -AllowFileRestore $false

Check Content

If public folders are not used this check is NA. Open the Exchange Management Shell and enter the following command: Get-PublicFolderDatabase| Select Name, Identity, AllowFileRestore If the value of 'AllowFileRestore' is not set to 'False', this is a finding.

IA Controls

ECSC-1

Mail quota settings must not restrict receiving mail.

Finding ID
Exch-1-301
Rule ID
SV-44011r2_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-301
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Mail quota settings control the maximum sizes of a user’s mailbox and the system’s response if these limits are exceeded. Mailbox data that is not monitored against a quota increases the risk of mail loss due to filled disk space, which can also render the system unavailable. Failure to allow mail receipt may impede users from receiving mission critical data.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxDatabase <'MailboxDatabaseName'> -ProhibitSendReceiveQuota 'Unlimited' If an alternate value is desired from ProhibitSendReceiveQuota, obtain signoff with risk acceptance and document in the EDSP.

Check Content

Open the Exchange Management Shell and enter the following command: Get-MailboxDatabase | Select Name, Identity, ProhibitSendReceiveQuota If the value of 'ProhibitSendReceiveQuota' is set to an alternate value, and has signoff and risk acceptance in the EDSP, this is not a finding. If the value of 'ProhibitSendReceiveQuota' is not set to 'Unlimited', this is a finding.

Mail Store storage quota must limit send.

Finding ID
Exch-1-303
Rule ID
SV-44013r1_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-303
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Mail quota settings control the maximum sizes of a user’s mailbox and the system’s response if these limits are exceeded. Mailbox data that is not monitored against a quota increases the risk of mail loss due to filled disk space, which can also render the system unavailable. There are multiple controls, which supply graduated levels of opportunity to respond before risking email service loss. This control prohibits the user from sending an email when the mailbox limit reaches the prohibit send quota value. Note: Best practice for this setting is to prohibit the user from sending email when the mailbox reaches 90 percent of capacity.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxDatabase <'MailboxDatabaseName'> -ProhibitSendQuota <'SitesProhibitSendQuotaLimit'>

Check Content

Obtain the Email Domain Security Plan (EDSP) and locate the value for 'Prohibit Send Quota Limit'. Open the Exchange Management Shell and enter the following command: Get-MailboxDatabase | Select Name, Identity, ProhibitSendQuota If the value of 'ProhibitSendQuota' is not set to the sites 'ProhibitSendQuotaLimit', this is a finding.

IA Controls

ECSC-1

Mail Store storage quota must issue a warning.

Finding ID
Exch-1-306
Rule ID
SV-44015r1_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-306
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Mail quota settings control the maximum sizes of a user’s mailbox and the system’s response if these limits are exceeded. Mailbox data that is not monitored against a quota increases the risk of mail loss due to filled disk space, which can also render the system unavailable. There are multiple controls, which supply graduated levels of opportunity to respond before risking data loss. This control sends the user a warning message that the mailbox is reaching its limit. The user at this point can still send and receive email. Note: Best practice is to send this warning when the mailbox reaches 75 percent of capacity.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxDatabase <'MailboxDatabaseName'> -IssueWarningQuota <'SitesIssueWarningQuota'>

Check Content

Obtain the Email Domain Security Plan (EDSP) and locate the value for 'IssueWarningQuota'. Open the Exchange Management Shell and enter the following command: Get-MailboxDatabase | Select Name, Identity, IssueWarningQuota If the value of 'IssueWarningQuota' is not set to the sites 'Issue Warning Quota', this is a finding.

IA Controls

ECSC-1

The Mailbox Stores must mount at startup.

Finding ID
Exch-1-309
Rule ID
SV-44017r1_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-309
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Administrator responsibilities include the ability to react to unplanned maintenance tasks or emergency situations that may require Mailbox data manipulation. Occasionally, there may be a need to start the server with 'unmounted' data stores, if manual maintenance is being performed on them. Failure to uncheck the 'do not mount on startup' condition will result in unavailability of mail services. Correct configuration of this control will prevent unplanned outages due to being enabled. On occasions when it is needed, care should be taken in process steps to clear the check box upon task completion, so that mail stores are available to users (unmounted mailbox stores are not available to users).

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxDatabase -Identity <'MailboxName'> -MountAtStartup $true

Check Content

Open the Exchange Management Shell and enter the following command: Get-MailboxDatabase | Select Name, Identity, MountAtStartup If the value of 'MountAtStartup' is not set to 'True', this is a finding.

IA Controls

ECSC-1

Mailboxes must be retained until backups are complete.

Finding ID
Exch-1-312
Rule ID
SV-44020r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-1-312
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Backup and recovery procedures are an important part of overall system availability and integrity. Complete backups reduce the chance of accidental deletion of important information, and make it possible to have complete recoveries. It is not uncommon for users to receive and delete messages in the scope of a single backup cycle. This setting ensures at least one backup has been run on the mailbox store before the message physically disappears. By enabling this setting, all messages written to recipients who have accounts on this store will reside in backups even if they have been deleted by the user before the backup has run.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxDatabase <'MailboxDatabase'> -RetainDeletedItemsUntilBackup $true

Check Content

Open the Exchange Management Shell and enter the following command: Get-MailboxDatabase| Select Name, Identity, RetainDeletedItemsUntilBackup If the value of 'RetainDeletedItemsUntilBackup' is not set to 'True', this is a finding.

IA Controls

ECSC-1

Mailbox database must not be overwritten by a restore.

Finding ID
Exch-1-315
Rule ID
SV-44022r1_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-315
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Email system availability depends in part on best practices strategies for setting tuning configurations. Unauthorized or accidental restoration of mailbox data risks data loss or corruption. This setting controls whether the mailbox store can be overwritten by a backup, which will cause loss of all information added after the backup was created. It should only be enabled during maintenance windows or following an outage (immediately before a restore is to be made), and cleared again immediately afterwards. During production windows, this feature must be disabled.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxDatabase <'MailboxDatabaseName'> -AllowFileRestore $false

Check Content

Open the Exchange Management Shell and enter the following command: Get-MailboxDatabase| Select Name, Identity, AllowFileRestore If the value of 'AllowFileRestore' is not set to 'False', this is a finding.

IA Controls

ECSC-1

Mailbox databases must reside on a dedicated partition.

Finding ID
Exch-1-318
Rule ID
SV-44024r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-1-318
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

In the same way that added security layers can provide a cumulative positive effect on security posture, multiple applications can provide a cumulative negative effect. A vulnerability and subsequent exploit to one application can lead to an exploit of other applications sharing the same security context. For example, an exploit to a web server process that leads to unauthorized administrative access to the host system can most likely lead to a compromise of all applications hosted by the same system. Email services should be installed to a discrete set of directories, on a partition that does not host other applications. Email services should never be installed on a Domain Controller / Directory Services server.

Fix Text

Configure the system to meet the separate partition requirement.

Check Content

Obtain the Email Domain Security Plan (EDSP) and locate the assigned directory for the mailbox server under review. Open the Exchange Management Shell and enter the following command to determine the drives the mailbox databases are located. Get-MailboxDatabase | Select Name, Identity, EdbFilePath Open Windows Explorer and use the file and folder properties function to verify the mailbox databases are on a dedicated partition. If not, this is a finding.

IA Controls

ECSC-1

Email forwarding must be restricted.

Finding ID
Exch-1-321
Rule ID
SV-44025r2_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-1-321
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Auto-forwarded email accounts do not meet the requirement for digital signature and encryption of CUI and PII IAW DoDI 8520.2 (reference ee) and DoD Director for Administration and Management memorandum, 'Safeguarding Against and Responding to the Breach of Personally Identifiable Information.’ Use of forwarding set by an administrator interferes with non-repudiation requirements that each end user be responsible for creation and destination of email data.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-Mailbox -Identity <'UserWithForwardedAddress'> -ForwardingSMTPAdddress $null

Check Content

Access Active Directory for mailbox enabled user accounts with the msExchGenericForwardingAddress attribute set. Obtain the Email Domain Security Plan (EDSP) and locate any accounts that have been authorized to have email auto-forwarded. Open the Exchange Management Shell and enter the following commands: Get-Mailbox -Filter {ForwardingSMTPAddress -ne $null} If any user has a forwarding SMTP address and is not documented in the EDSP, this is a finding. Note: If no remote SMTP domain matching the mail-enabled user or contact that allows forwarding is configured for users identified with a forwarding address, this function will not work properly. This requirement works with Exch-1-324.

Email Diagnostic log level must be set to low or lowest level.

Finding ID
Exch-2-817
Rule ID
SV-44026r2_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-817
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Log files help establish a history of activities, and can be useful in detecting attack attempts or determining tuning adjustments to improve availability. Diagnostic logging, however, characteristically produces large volumes of data and requires care in managing the logs to prevent risk of disk capacity denial of service conditions. Exchange diagnostic logging is broken up into 29 main “services”, each of which has anywhere from 2 to 26 “categories” of events to be monitored. Moreover, each category may be set to one of four levels of logging: Lowest, Low, Medium, and High, depending on how much detail one desires. The higher the level of detail, the more disk space required to store the audit material. Diagnostic logging is intended to help administrators debug problems with their systems, not as a general purpose auditing tool. Because the diagnostic logs collect a great deal of information, the log files may grow huge very quickly. Diagnostic log levels may be raised for limited periods of time when attempting to debug relevant pieces of Exchange functionality. Once debugging has finished, diagnostic log levels should be reduced again.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-EventLogLevel -Identity <ServiceName\Name> -Level Lowest or Set-EventLogLevel -Identity <ServiceName\Name> -Level Low

Check Content

Open the Exchange Management Shell and enter the following command: Get-EventLogLevel If any Diagnostic “EventLevel” is not set to “Low” or “Lowest”, this is a finding.

The Send Fatal Errors to Microsoft must be disabled.

Finding ID
Exch-2-820
Rule ID
SV-44028r2_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-820
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Log files help establish a history of activities, and can be useful in detecting attack attempts or determining tuning adjustments to improve availability. This setting enables an automated log entry to be sent to Microsoft giving general details about the nature and location of the error. Microsoft, in turn, uses this information to improve the robustness of their product. While this type of debugging information would not ordinarily contain sensitive information, it may alert eavesdroppers to the existence of problems in your Exchange organization. At the very least, it could alert them to (possibly) advantageous timing to mount an attack. At worst, it may provide them with information as to which aspects of Exchange are causing problems and might be vulnerable (or at least sensitive) to attack. All system errors in Exchange will result in outbound traffic that may be identified by an eavesdropper. For this reason, the 'Report Fatal Errors to Microsoft' feature must be disabled.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-ExchangeServer -Identity <'ServerName'> -ErrorReportingEnabled $false

Check Content

Open the Exchange Management Shell and enter the following command: Get-ExchangeServer –status | Select Name, Identity, ErrorReportingEnabled If the value of 'ErrorReportingEnabled' is not set to 'False', this is a finding.

Administrator audit logging must be enabled.

Finding ID
Exch-2-823
Rule ID
SV-44029r2_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-823
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Unauthorized or malicious data changes can compromise the integrity and usefulness of the data. Automated attacks or malicious users with elevated privileges have the ability to affect change using the same mechanisms as email administrators. Auditing changes to access mechanisms not only supports accountability and non-repudiation for those authorized to define the environment but also enables investigation of changes made by others who may not be authorized. Note: This administrator auditing feature audits all exchange changes regardless of the users' assigned role or permissions.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-AdminAuditLogConfig -AdminAuditLogEnabled $true

Check Content

Open the Exchange Management Shell and enter the following command: Get-AdminAuditLogConfig | Select AdminAuditLogEnabled If the value of 'AdminAuditLogEnabled' is not set to 'True', this is a finding.

Audit data must be protected against unauthorized access.

Finding ID
Exch-2-826
Rule ID
SV-44031r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-826
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Log files help establish a history of activities, and can be useful in detecting attack attempts or determining tuning adjustments to improve availability. Audit log content must always be considered sensitive, and in need of protection. Audit data available for modification by a malicious user can be altered to conceal malicious activity. Audit data might also provide a means for the malicious user to plan unauthorized activities that exploit weaknesses. The contents of audit logs are protected against unauthorized access, modification, or deletion. Only authorized auditors and the audit functions should be granted Read and Write access to audit log data.

Fix Text

Restrict any unauthorized groups or users from accessing the audit logs.

Check Content

Obtain the Email Domain Security Plan (EDSP) and locate the authorized groups or users that should have access to the audit data. If any group or user has access to the audit data that is not documented in the EDSP, this is a finding.

IA Controls

ECSC-1

Circular Logging must be disabled.

Finding ID
Exch-1-802
Rule ID
SV-44032r2_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-1-802
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Logging provides a history of events performed, and can also provide evidence of tampering or attack. Failure to create and preserve logs adds to the risk that suspicious events may go unnoticed, or the raise the potential that insufficient history will be available to investigate them. This setting controls how log files are written. If circular logging is enabled, there is one log file stored with a default size of 1024 KB. Once the size limit has been reached, additional log entries overwrite the oldest log entries. If circular logging is disabled, once a log file reaches the size limit, a new log file is created. Mailbox should not use circular logging. Logs should be written to a partition separate from the operating system, with log protection and backups being incorporated into the overall System Security plan.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxDatabase -Identity <'MailboxDatabase'> -CircularLoggingEnabled $false

Check Content

Open the Exchange Management Shell and enter the following command: Get-MailboxDatabase -Server <'ServerUnderReview'>| Select Name, Identity, CircularLoggingEnabled If the value of 'CircularLoggingEnabled' is not set to 'False', this is a finding.

Exchange application directory must be protected from unauthorized access.

Finding ID
Exch-2-828
Rule ID
SV-44033r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-828
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Default product installations may provide more generous access permissions than are necessary to run the application. By examining and tailoring access permissions to more closely provide the least amount of privilege possible, attack vectors that align with user permissions are less likely to access more highly secured areas.

Fix Text

Locate the Exchange application directory and Remove or modify the group or user access permissions. Note: The default installation directory is \Program Files\Microsoft\Exchange Server\V14.

Check Content

Obtain the Email Domain Security Plan (EDSP) and locate the authorized groups and users that have access to the Exchange application directories. Verify the access permissions on the directory match the access permissions listed in the EDSP. If any group or user has different access permissions, this is a finding. Note: The default installation directory is \Program Files\Microsoft\Exchange Server\V14.

IA Controls

ECSC-1

Email Subject Line logging must be disabled.

Finding ID
Exch-1-805
Rule ID
SV-44034r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-1-805
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Log files help establish a history of activities, and can be useful in detecting attack attempts or determining tuning adjustments to improve availability. When “message tracking” is enabled, only the sender, recipients, time, and other delivery information are included by default. Information such as the subject and message body is not included. However, the absence of the message subject line can make it difficult to locate a specific message in the log unless one knows roughly what time the message was sent. To simplify searches through these logs, Exchange offers the ability to include the message “subject line” in the log files and in the Message Tracking Center display. This can make it significantly easier to locate a specific message. This feature creates larger log files and will contain information that may raise privacy and legal concerns - enterprise policy should be consulted before this feature is enabled. Also, since the log files may contain sensitive information in the form of the subject line, the log files will need to be protected, commensurate with the sensitivity level, as the content may be of interest to an attacker. For these reasons, it is recommended that subject logging not be enabled during regular production operations, but instead treat this feature as a diagnostic that can be used if needed. The tradeoff of this is that finding the correct message in the message tracking logs will become more difficult since the administrator will need to search using only the time the message was sent and the message’s sender. This control will have no effect unless Message Tracking is enabled. That said, the setting should be disabled in case message tracking is perchance enabled at a future time.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxServer -Identity <'ServerName'> -MessageTrackingLogSubjectLoggingEnabled $false

Check Content

Open the Exchange Management Shell and enter the following command: Get-MailboxServer | Select Name, Identity, MessageTrackingLogSubjectLoggingEnabled If the value of 'MessageTrackingLogSubjectLoggingEnabled' is not set to 'False', this is a finding.

IA Controls

ECSC-1

Message Tracking Logging must be enabled.

Finding ID
Exch-1-808
Rule ID
SV-44035r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-1-808
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

A message tracking log provides a detailed log of all message activity as messages are transferred to and from a computer running Exchange. If events are not recorded it may be difficult or impossible to determine the root cause of system problems or the unauthorized activities of malicious users.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-MailboxServer -Identity <'ServerName'> -MessageTrackingLogEnable $True

Check Content

Open the Exchange Management Shell and enter the following command: Get-MailboxServer | Select Name, Identity, MessageTrackingLogEnabled If the value of 'MessageTrackingLogEnabled' is not set to 'True', this is a finding.

IA Controls

ECSC-1

Exchange must not send Customer Experience reports to Microsoft.

Finding ID
Exch-2-831
Rule ID
SV-44036r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-831
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Log files help establish a history of activities, and can be useful in detecting attack attempts or determining tuning adjustments to improve availability. This setting enables an automated entry to be sent to Microsoft giving general details about how the product is used. Microsoft, in turn, uses this information to improve the robustness of their product. While this type of information does not ordinarily contain sensitive information, it may alert eavesdroppers to the existence of the environment and its configurations. It could alert them to (possibly) advantageous timing or weaknesses toward which to mount an attack.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-OrganizationConfig -CustomerFeedbackEnabled $false

Check Content

Open the Exchange Management Shell and enter the following command: Get-OrganizationConfig If the value for CustomerFeedbackEnabled is not set to 'False', this is a finding.

IA Controls

ECSC-1

Audit record parameters must be set.

Finding ID
Exch-2-833
Rule ID
SV-44037r2_rule
Severity
Cat III
CCE
(None)
Group Title
Exch-2-833
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Log files help establish a history of activities, and can be useful in detecting attack attempts. This item declares the fields that must be available in the audit log file in order to adequately research events that are logged. Audit records should include the following fields to supply useful event accounting: Object modified, Cmdlet name, Cmdlet parameters, Modified parameters, Caller, Succeeded, and Originating server.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-AdminAuditLogConfig -AdminAuditLogParameters *

Check Content

Open the Exchange Management Shell and enter the following command: Get-AdminAuditLogConfig | Select AdminAuditLogParameters If the value of 'AdminAuditLogParameters' is not set to '{*}', this is a finding. Note: The value of {*} indicates all parameters are being audited.

Audit data must be on separate partitions.

Finding ID
Exch-2-839
Rule ID
SV-44038r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-839
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Log files help establish a history of activities, and can be useful in detecting attack attempts or determining tuning adjustments to improve availability. Audit log content must always be considered sensitive, and in need of protection. Successful exploit of an application server vulnerability may well be logged by monitoring or audit processes when it occurs. By writing log and audit data to a separate partition where separate security contexts protect them, it may offer the ability to protect this information from being modified or removed by the exploit mechanism.

Fix Text

Configure the audit log location to be on a partition drive separate from the application. Document the location in the EDSP.

Check Content

Obtain the Email Domain Security Plan (EDSP) and locate the audit logs assigned partition. By default the logs are located on the application partition in '\Program Files\Microsoft\Exchange Server\V14\Logging\'. If the log files are not on a separate partition from the application, this is a finding.

IA Controls

ECSC-1

Queue monitoring must be configured with threshold and action.

Finding ID
Exch-2-842
Rule ID
SV-44039r3_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-842
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Monitors are automated “process watchers” that respond to performance changes, and can be useful in detecting outages and alerting administrators where attention is needed. Exchange has built-in monitors that enable the administrator to generate alerts if thresholds are reached, better enabling them to react in a timely fashion. The intent of this check is for system administrators to have awareness of performance changes on their network. Notification choices include email an alert to an email-enabled account, for example, an email Administrator, or invoke a script to take other action, for example, to add an Event to the Microsoft Application Event Log, where external monitors might detect it. Data elements configured to be monitored should be specific to the organization’s network. .

Fix Text

Open the Exchange Management Console In the left pane, navigate to and select Microsoft Exchange On-Premises <server.domain> --> Toolbox In the Right pane double click on Performance Monitor In the left pane, navigate to and select Performance Logs and Alerts --> Data Collector Sets --> User Defined Right click on User Defined and configure the system to use User Defined data collection for monitoring the queues.

Check Content

Note: If a third-party application is performing monitoring functions, the reviewer should verify the application is monitoring correctly and mark the vulnerability NA. Open the Exchange Management Shell and enter the following command: perfmon In the left pane, expand and navigate Data Collector Sets >> User Defined. If no sets are defined or queues are not being monitored, this is a finding.

Email software must be monitored for change on INFOCON frequency schedule.

Finding ID
Exch-3-003
Rule ID
SV-44040r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-3-003
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

The INFOCON system provides a framework within which the Commander USSTRATCOM regional commanders, service chiefs, base/post/camp/station/vessel commanders, or agency directors can increase the measurable readiness of their networks to match operational priorities. The readiness strategy provides the ability to continuously maintain and sustain one’s own information systems and networks throughout their schedule of deployments, exercises, and operational readiness life cycle independent of network attacks or threats. The system provides a framework of prescribed actions and cycles necessary for reestablishing the confidence level and security of information systems for the commander and thereby supporting the entire Global Information Grid (GIG) (SD 527-1 Purpose). The Exchange software files and directories are vulnerable to unauthorized changes if not adequately protected. An unauthorized change could affect the integrity or availability of email services overall. For this reason, all application software installations must monitor for change against a software baseline that is preserved when installed, and updated periodically as patches or upgrades are installed. Automated and manual schedules for software change monitoring must be compliant with SD527-1 frequencies. Note: Policy Auditor 5.2 or later, File Integrity Monitor (FIM) module will meet the requirement for file integrity checking. The Asset module within HBSS does not meet this requirement.

Fix Text

Implement a process to compare software against a baseline (*.exe, *.bat, *.com, *.cmd, and *.dll) on a frequency required by the prevailing INFOCON level. Document the process and output artifacts in the EDSP.

Check Content

Access the EDSP baseline section and determine the process and frequency for identifying software changes (*.exe, *.bat, *.com, *.cmd, and *.dll) on servers against a baseline. Examine artifacts identified as outputs of this process. If baseline comparisons are not done on the INFOCON-required schedule, this is a finding.

IA Controls

ECSC-1

Exchange software baseline copy must exist.

Finding ID
Exch-3-006
Rule ID
SV-44041r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-3-006
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Exchange software, as with other application software installed on a host system, must be included in a system baseline record and periodically reviewed; otherwise unauthorized changes to the software may not be discovered. This effort is a vital step to securing the host and the applications, as it is the only method that may provide the ability to detect and recover from otherwise undetected changes, such as those that result from worm or bot intrusions. The Exchange software and configuration baseline is created and maintained for comparison during scanning efforts. Operational procedures must include baseline updates as part of configuration management tasks that change the software and configuration.

Fix Text

Implement email software baseline process. Document the details in the EDSP.

Check Content

Access the EDSP and locate the baseline documentation. Review the application software baseline procedures and implementation artifacts. Note the list of files and directories included in the baseline procedure for completeness. If an email software copy exists to serve as a baseline and is available for comparison during scanning efforts, this is not a finding.

IA Controls

ECSC-1

Services must be documented and unnecessary services must be removed or disabled.

Finding ID
Exch-3-804
Rule ID
SV-44043r2_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-3-804
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Unneeded, but running, services offer attackers an enhanced attack profile, and attackers are constantly watching to discover open ports with running services. By analyzing and disabling unneeded services, the associated open ports become unresponsive to outside queries, and servers become more secure as a result. Exchange Server has role-based server deployment to enable protocol path control and logical separation of network traffic types. For example, a server implemented in the Client Access role (i.e., Outlook Web App [OWA]) is configured and tuned as a web server using web protocols. A client access server exposes only web protocols (HTTP/HTTPS) enabling system administrators to optimize the protocol path and disable all services unnecessary for Exchange web services. Similarly, servers created to host mailboxes are dedicated to that task, and must operate only the services needed for mailbox hosting. (Exchange servers must also operate some Web services, but only to the degree that Exchange requires the IIS engine in order to function). Because POP3, and IMAP4 clients are not included in the standard desktop offering, they must be disabled.

Fix Text

Document the services required for the system to operate. Remove or disable any services that are not required.

Check Content

To view system services open a windows power shell and enter the following command: Get-Service | Where-Object {$_.status -eq 'running'} The command returns a list of installed services and the status of that service. Required services will vary between organizations, and will vary depending on the role of the individual system. Organizations will develop their own list of services which will be documented and justified with the ISSO. The Site’s list will be provided for any security review. Services that are common to multiple systems can be addressed in one document. Exceptions for individual systems should be identified separately by system. If the site has not documented the services required for their system(s), this is a finding. If any undocumented or unnecessary services are running, then this is a finding.

Email application must not share a partition with another application.

Finding ID
Exch-3-807
Rule ID
SV-44045r2_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-3-807
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

In the same way that added security layers can provide a cumulative positive effect on security posture, multiple applications can provide a cumulative negative effect. A vulnerability and subsequent exploit to one application can lead to an exploit of other applications sharing the same security context. For example, an exploit to a web server process that leads to unauthorized administrative access to the host system can most likely lead to a compromise of all applications hosted by the same system. Email services should be installed on a partition that does not host other applications. Email services should never be installed on a Domain Controller / Directory Services server.

Fix Text

Install Exchange on a dedicated application partition separate than that of the OS.

Check Content

Access Windows Explorer and identify the OS partition. Navigate to configured partitions, and access the ‘Program Files’ directory. Note the installation partition for Microsoft Exchange. If Exchange resides on a partition other than that of the OS, and does not have other applications installed (without associated approval from the ISSO), this is not a finding.

Servers must use approved DoD certificates.

Finding ID
Exch-2-014
Rule ID
SV-44046r2_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-014
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Server certificates are required for many security features in Exchange; without them the server cannot engage in many forms of secure communication. Failure to implement valid certificates makes it virtually impossible to secure Exchange's communications.

Fix Text

Remove the non-DoD certificate and import the correct DoD certificates.

Check Content

Open the Exchange Management Shell and enter the following command: Get-ExchangeCertificate | Select CertificateDomains, issuer If the value of 'CertificateDomains' does not indicate it is issued by the DoD, this is a finding.

Email servers must have Email aware virus protection.

Finding ID
Exch-3-811
Rule ID
SV-44048r1_rule
Severity
Cat I
CCE
(None)
Group Title
Exch-3-811
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

With the proliferation of trojans, viruses, and SPAM attaching themselves to email messages (or attachments), it is necessary to have capable email Aware Anti-Virus (AV) products to scan messages and identify any resident malware. Because email messages and their attachments are formatted to the MIME standard, a flat-file AV scanning engine is not suitable for scanning email message stores. Email aware Anti-Virus engines must be Exchange 2010 compliant, or use VirusScan Application Program Interface (VSAPI) version 2.6 or higher, which is able to scan email MIME content safely. Competent email scanners will have the ability to scan mail stores, attachments (including zip or other archive files) and mail queues, and to issue warnings or alerts if malware is detected. As with other AV products, a necessary feature to include is the ability for automatic updates.

Fix Text

Install or upgrade scanning products to VSAPI version 2.6 or higher. Configure mail stores to be scanned with products at VSAPI version 2.6 or higher.

Check Content

Obtain the email Domain Security Plan (EDSP) and locate the anti-virus strategy information. Validate that the message stores AV scanner product is Exchange 2010 compatible or VSAPI 2.6 compliant. If email servers are using email-aware AV product that is Exchange 2010 compliant or has VSAPI version 2.6 or higher, this is not a finding.

IA Controls

ECSC-1

The current, approved service pack must be installed.

Finding ID
Exch-3-814
Rule ID
SV-44049r3_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-3-814
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Failure to install the most current Exchange service pack leaves a system vulnerable to exploitation. Current service packs correct known security and system vulnerabilities.

Fix Text

Update the system with the latest approved service pack or a supported release.

Check Content

Open the Exchange Management Shell and enter the following command: Get-ExchangeServer | fl name, AdminDisplayVersion If the value of 'AdminDisplayVersion' does not return Version 14.2 (Build 247.5) or greater, this is a finding.

Local machine policy must require signed scripts.

Finding ID
Exch-2-019
Rule ID
SV-44052r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-2-019
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Scripts often provide a way for attackers to infiltrate a system, especially those downloaded from untrusted locations. By setting machine policy to prevent unauthorized script executions, unanticipated system impacts can be avoided. Failure to allow only signed remote scripts reduces the attack vector vulnerabilities from unsigned remote scripts.

Fix Text

Open the Exchange Management Shell and enter the following command: Set-ExecutionPolicy RemoteSigned

Check Content

Open the Exchange Management Shell and enter the following command: Get-ExecutionPolicy If the value of 'LocalMachine' does not return a value of 'RemoteSigned', this is a finding.

IA Controls

ECSC-1

Email forwarding SMTP domains must be restricted.

Finding ID
Exch-1-324
Rule ID
SV-50976r1_rule
Severity
Cat II
CCE
(None)
Group Title
Exch-1-324
CCI
(None)
Target Key
(None)
Documentable
No
Discussion

Auto-forwarded email accounts do not meet the requirement for digital signature and encryption of CUI and PII IAW DoDI 8520.2 (reference ee) and DoD Director for Administration and Management memorandum, 'Safeguarding Against and Responding to the Breach of Personally Identifiable Information.’ Use of forwarding set by an administrator interferes with non-repudiation requirements that each end user be responsible for creation and destination of email data.

Fix Text

Open the Exchange Management Shell and enter the following command: Set- RemoteDomain -Identity <RemoteDomainIdParameter>

Check Content

Obtain the Email Domain Security Plan (EDSP) and locate any accounts that have been authorized to have email auto-forwarded. Open the Exchange Management Shell and enter the following commands: Get-RemoteDomain | select name, AutoForwardEnabled If any domain for user forwarding SMTP address is not documented in the EDSP, this is a finding. Note: If no remote SMTP domain matching the mail-enabled user or contact that allows forwarding is configured for users identified with a forwarding address, this function will not work properly. This requirement works with Exch-1-321.

IA Controls

ECSC-1