MS Exchange 2013 Mailbox Server Security Technical Implementation Guide

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: [email protected]

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Version / Release: V1R6

Published: 2019-12-23

Updated At: 2020-01-27 23:27:08

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Drop CKL or SCAP (XCCDF) results here.

    Vuln Rule Version CCI Severity Title Description Status Finding Details Comments
    SV-84563r1_rule EX13-MB-000005 CCI-001403 MEDIUM Exchange must have Administrator audit logging enabled. 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 effect change using the same mechanisms as email administrators. Auditing c
    SV-84565r1_rule EX13-MB-000010 CCI-000213 MEDIUM Exchange Servers must use approved DoD certificates. 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 communicati
    SV-84567r1_rule EX13-MB-000015 CCI-001368 MEDIUM Exchange auto-forwarding email to remote domains must be disabled or restricted. Attackers can use automated messages to determine whether a user account is active, in the office, traveling, and so on. An attacker might use this information to conduct future attacks. Verify Automatic Forwards to remote domains are disabled, except for
    SV-84569r1_rule EX13-MB-000020 CCI-000169 MEDIUM Exchange Connectivity logging must be enabled. A connectivity log is a record of the SMTP connection activity of the outbound message delivery queues to the destination Mailbox server, smart host, or domain. Connectivity logging is available on Hub Transport servers and Edge Transport servers. By defa
    SV-84571r1_rule EX13-MB-000025 CCI-000169 MEDIUM The Exchange Email Diagnostic log level must be set to the lowest level. 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
    SV-84573r1_rule EX13-MB-000030 CCI-000169 LOW Exchange Audit record parameters must be set. 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 inc
    SV-84575r1_rule EX13-MB-000035 CCI-000133 LOW Exchange Circular Logging must be disabled. 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 and raises the potential that insufficient history will be av
    SV-84577r4_rule EX13-MB-000040 CCI-000133 MEDIUM Exchange Email Subject Line logging must be disabled. 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 inform
    SV-84579r2_rule EX13-MB-000045 CCI-000133 MEDIUM Exchange Message Tracking Logging must be enabled. 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 th
    SV-84581r1_rule EX13-MB-000050 CCI-000154 MEDIUM Exchange Queue monitoring must be configured with threshold and action. 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
    SV-84583r1_rule EX13-MB-000055 CCI-000381 MEDIUM Exchange Send Fatal Errors to Microsoft must be disabled. It is detrimental for applications 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
    SV-84585r1_rule EX13-MB-000060 CCI-000162 MEDIUM Exchange must protect audit data against unauthorized read access. 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 availabl
    SV-84587r1_rule EX13-MB-000065 CCI-000381 MEDIUM Exchange must not send Customer Experience reports to Microsoft. It is detrimental for applications 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
    SV-84589r1_rule EX13-MB-000070 CCI-000163 MEDIUM Exchange must protect audit data against unauthorized access. 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 availabl
    SV-84591r1_rule EX13-MB-000075 CCI-000164 MEDIUM Exchange must protect audit data against unauthorized deletion. 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 availabl
    SV-84593r1_rule EX13-MB-000080 CCI-001348 MEDIUM Exchange Audit data must be on separate partitions. 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 expl
    SV-84595r1_rule EX13-MB-000085 CCI-001749 MEDIUM Exchange Local machine policy must require signed scripts. 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
    SV-84597r2_rule EX13-MB-000090 CCI-000381 MEDIUM The Exchange IMAP4 service must be disabled. The IMAP4 protocol is not approved for use within the DoD. It uses a clear-text-based user name and password and does not support the DoD standard for PKI for email access. User name and password could easily be captured from the network, allowing a malic
    SV-84599r2_rule EX13-MB-000095 CCI-000381 MEDIUM The Exchange POP3 service must be disabled. The POP3 protocol is not approved for use within the DoD. It uses a clear-text-based user name and password and does not support the DoD standard for PKI for email access. User name and password could easily be captured from the network, allowing a malici
    SV-84601r1_rule EX13-MB-000100 CCI-001082 MEDIUM Exchange Mailbox databases must reside on a dedicated partition. 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 ot
    SV-84603r1_rule EX13-MB-000105 CCI-001178 MEDIUM Exchange Internet-facing Send connectors must specify a Smart Host. When identifying a "Smart Host" for the email environment, a logical Send connector is the preferred method. A Smart Host acts as an Internet-facing concentrator for other email servers. Appropriate hardening can be applied to the Smart Host, rather than
    SV-84605r1_rule EX13-MB-000110 CCI-001184 MEDIUM Exchange internal Receive connectors must require encryption. The Simple Mail Transfer Protocol (SMTP) Receive connector is used by Exchange to send and receive messages from server to server using SMTP protocol. This setting controls the encryption strength used for client connections to the SMTP Receive connector.
    SV-84607r1_rule EX13-MB-000115 CCI-001184 MEDIUM Exchange internal Send connectors must use Domain Security (mutual authentication Transport Layer Security). The Simple Mail Transfer Protocol (SMTP) connector is used by Exchange to send and receive messages from server to server. There are several controls that work together to provide security between internal servers. This setting controls the authentication
    SV-84609r1_rule EX13-MB-000120 CCI-001184 MEDIUM Exchange internal Send connectors must require encryption. The Simple Mail Transfer Protocol (SMTP) connector is used by Exchange to send and receive messages from server to server. There are several controls that work together to provide security between internal servers. This setting controls the encryption met
    SV-84611r1_rule EX13-MB-000125 CCI-001199 MEDIUM Exchange Public Folder stores must be retained until backups are complete. 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
    SV-84613r1_rule EX13-MB-000130 CCI-001199 LOW The Exchange Public Folder database must not be overwritten by a restore. Email system availability depends in part on best practice 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 c
    SV-84615r1_rule EX13-MB-000135 CCI-001199 MEDIUM Exchange Mailboxes must be retained until backups are complete. 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
    SV-84617r1_rule EX13-MB-000140 CCI-001199 LOW The Exchange Mailbox database must not be overwritten by a restore. Email system availability depends in part on best practice 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 overw
    SV-84619r2_rule EX13-MB-000145 CCI-001199 MEDIUM Exchange email forwarding must be restricted. 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
    SV-84621r1_rule EX13-MB-000150 CCI-001199 MEDIUM Exchange email-forwarding SMTP domains must be restricted. 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
    SV-84623r1_rule EX13-MB-000155 CCI-001094 LOW Exchange Mail quota settings must not restrict receiving mail. 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 rende
    SV-84625r1_rule EX13-MB-000160 CCI-001094 LOW Exchange Mail Quota settings must not restrict receiving mail. 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 rende
    SV-84627r1_rule EX13-MB-000165 CCI-001094 LOW The Exchange Mail Store storage quota must issue a warning. 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 rende
    SV-84629r1_rule EX13-MB-000170 CCI-001094 LOW Exchange Mailbox Stores must mount at startup. 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 mai
    SV-84631r1_rule EX13-MB-000175 CCI-001095 LOW Exchange Message size restrictions must be controlled on Receive connectors. Email system availability depends in part on best practice strategies for setting tuning configurations. For message size restrictions, multiple places exist to set or override inbound or outbound message size. Failure to control the configuration strateg
    SV-84633r1_rule EX13-MB-000180 CCI-001095 LOW Exchange Receive connectors must control the number of recipients per message. Email system availability depends in part on best practice strategies for setting tuning configurations. This configuration controls the maximum number of recipients who will receive a copy of a message at one time. This tunable value is related to thro
    SV-84635r1_rule EX13-MB-000185 CCI-001095 LOW Exchange Receive connectors must be clearly named. For Receive connectors, unclear naming as to direction and purpose increases risk that messages may not flow as intended, troubleshooting efforts may be impaired, or incorrect assumptions may be made about the completeness of the configuration. Collect
    SV-84637r1_rule EX13-MB-000190 CCI-001095 LOW The Exchange Receive Connector Maximum Hop Count must be 60. Email system availability depends in part on best practice strategies for setting tuning configurations. This setting controls the maximum number of hops (email servers traversed) a message may take as it travels to its destination. Part of the original I
    SV-84639r1_rule EX13-MB-000195 CCI-001095 LOW Exchange Send connectors must be clearly named. For Send connectors, unclear naming as to direction and purpose increases risk that messages may not flow as intended, troubleshooting efforts may be impaired, or incorrect assumptions may be made about the completeness of the configuration. Collective
    SV-84641r1_rule EX13-MB-000200 CCI-001095 LOW Exchange Send connectors delivery retries must be controlled. This setting controls the rate at which delivery attempts from the home domain are retried and user notifications are issued and notes the expiration time when the message will be discarded. If delivery retry attempts are too frequent, servers will gen
    SV-84643r1_rule EX13-MB-000205 CCI-001095 LOW Exchange Message size restrictions must be controlled on Send connectors. Email system availability depends in part on best practice strategies for setting tuning configurations. For message size restrictions, multiple places exist to set or override inbound or outbound message size. Failure to control the configuration strateg
    SV-84645r1_rule EX13-MB-000210 CCI-001095 LOW The Exchange Send connector connections count must be limited. The Exchange Send connector setting controls the maximum number of simultaneous outbound connections allowed for a given SMTP connector and can be used to throttle the SMTP service if resource constraints warrant it. If the limit is too low, connections m
    SV-84647r1_rule EX13-MB-000215 CCI-001095 LOW The Exchange global inbound message size must be controlled. Email system availability depends in part on best practice strategies for setting tuning configurations. Message size limits should be set to 10 megabytes at most, but often are smaller, depending on the organization. The key point in message size is that
    SV-84649r1_rule EX13-MB-000220 CCI-001095 LOW The Exchange global outbound message size must be controlled. Email system availability depends in part on best practice strategies for setting tuning configurations. Message size limits should be set to 10 megabytes at most, but often are smaller, depending on the organization. The key point in message size is that
    SV-84651r1_rule EX13-MB-000225 CCI-001095 LOW The Exchange Outbound Connection Limit per Domain Count must be controlled. Email system availability depends in part on best practice strategies for setting tuning configurations. This configuration controls the maximum number of simultaneous outbound connections from a domain and works in conjunction with the Maximum Outbound C
    SV-84653r1_rule EX13-MB-000230 CCI-001095 LOW The Exchange Outbound Connection Timeout must be 10 minutes or less. Email system availability depends in part on best practice strategies for setting tuning configurations. This configuration controls the number of idle minutes before the connection is dropped. It works in conjunction with the Maximum Outbound Connections
    SV-84655r1_rule EX13-MB-000235 CCI-001308 MEDIUM Exchange Internal Receive connectors must not allow anonymous connections. This control is used to limit the servers that may use this server as a relay. If a Simple Mail Transport Protocol (SMTP) sender does not have a direct connection to the Internet (for example, an application that produces reports to be emailed) then it wi
    SV-84657r1_rule EX13-MB-000240 CCI-001308 MEDIUM Exchange external/Internet-bound automated response messages must be disabled. Spam originators, in an effort to refine mailing lists, sometimes monitor transmissions for automated bounce-back messages. Automated messages include such items as "Out of Office" responses, nondelivery messages, or automated message forwarding. Automat
    SV-84659r1_rule EX13-MB-000245 CCI-001308 MEDIUM Exchange must have antispam filtering installed. Originators of spam messages are constantly changing their techniques in order to defeat spam countermeasures; therefore, spam software must be constantly updated to address the changing threat. A manual update procedure is labor intensive and does not sc
    SV-84661r1_rule EX13-MB-000250 CCI-001308 MEDIUM Exchange must have antispam filtering enabled. Originators of spam messages are constantly changing their techniques in order to defeat spam countermeasures; therefore, spam software must be constantly updated to address the changing threat. A manual update procedure is labor intensive and does not sc
    SV-84663r1_rule EX13-MB-000255 CCI-001308 MEDIUM Exchange must have antispam filtering configured. Originators of spam messages are constantly changing their techniques in order to defeat spam countermeasures; therefore, spam software must be constantly updated to address the changing threat. A manual update procedure is labor intensive and does not sc
    SV-84665r2_rule EX13-MB-000260 CCI-001308 MEDIUM Exchange must not send automated replies to remote domains. Attackers can use automated messages to determine whether a user account is active, in the office, traveling, and so on. An attacker might use this information to conduct future attacks. Remote users will not receive automated "Out Of Office" delivery rep
    SV-84667r1_rule EX13-MB-000265 CCI-001308 HIGH Exchange servers must have an approved DoD email-aware virus protection software installed. With the proliferation of trojans, viruses, and spam attaching themselves to email messages (or attachments), it is necessary to have capable email-aware antivirus (AV) products to scan messages and identify any resident malware. Because email messages an
    SV-84669r1_rule EX13-MB-000270 CCI-001308 LOW The Exchange Global Recipient Count Limit must be set. Email system availability depends in part on best practice strategies for setting tuning configurations. The Global Recipient Count Limit field is used to control the maximum number of recipients that can be specified in a single message sent from this se
    SV-84671r1_rule EX13-MB-000275 CCI-002361 LOW The Exchange Receive connector timeout must be limited. Email system availability depends in part on best practice strategies for setting tuning. This configuration controls the number of idle minutes before the connection is dropped. It works in conjunction with the Maximum Inbound Connections Count setting.
    SV-84673r1_rule EX13-MB-000280 CCI-001879 LOW The Exchange Public Store storage quota must be limited. 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 F
    SV-84675r1_rule EX13-MB-003031 CCI-001242 MEDIUM A DoD-approved third party Exchange-aware malicious code protection application must be implemented. Malicious code protection mechanisms include, but are not limited, to, anti-virus and malware detection software. In order to minimize potential negative impact to the organization that can be caused by malicious code, it is imperative that malicious code
    SV-84677r1_rule EX13-MB-003030 CCI-001242 MEDIUM The applications built-in Malware Agent must be disabled. Malicious code protection mechanisms include, but are not limited, to, anti-virus and malware detection software. In order to minimize potential negative impact to the organization that can be caused by malicious code, it is imperative that malicious code
    SV-84679r1_rule EX13-MB-000345 CCI-000366 LOW Exchange Public Folder Stores must mount at startup. 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 i
    SV-84681r1_rule EX13-MB-000340 CCI-002605 MEDIUM Exchange must have the most current, approved service pack installed. Failure to install the most current Exchange service pack leaves a system vulnerable to exploitation. Current service packs correct known security and system vulnerabilities.
    SV-84683r2_rule EX13-MB-000335 CCI-002385 MEDIUM Exchange must provide Mailbox databases in a highly available and redundant configuration. To protect Exchange Server mailbox databases and the data they contain by configuring Mailbox servers and databases for high availability and site resilience. A database availability group (DAG) is a component of the Mailbox server high availability and
    SV-84687r1_rule EX13-MB-000325 CCI-002385 MEDIUM The Exchange SMTP automated banner response must not reveal server details. Automated connection responses occur as a result of FTP or Telnet connections, when connecting to those services. They report a successful connection by greeting the connecting client and stating the name, release level, and (often) additional information
    SV-84689r1_rule EX13-MB-000285 CCI-001812 MEDIUM The Exchange application directory must be protected from unauthorized access. 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 w
    SV-84691r1_rule EX13-MB-000290 CCI-001813 MEDIUM An Exchange software baseline copy must exist. 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
    SV-84693r1_rule EX13-MB-000295 CCI-001814 MEDIUM Exchange software must be monitored for unauthorized changes. Monitoring software files for changes against a baseline on a regular basis may help detect the possible introduction of malicious code on a system.
    SV-84695r1_rule EX13-MB-000300 CCI-001762 MEDIUM Exchange services must be documented and unnecessary services must be removed or disabled. 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 ou
    SV-84697r1_rule EX13-MB-000305 CCI-001953 MEDIUM Exchange Outlook Anywhere (OA) clients must use NTLM authentication to access email. Identification and authentication provide the foundation for access control. Access to email services applications require NTLM authentication. Outlook Anywhere, if authorized for use by the site, must use NTLM authentication when accessing email. Note:
    SV-84699r1_rule EX13-MB-000310 CCI-002530 MEDIUM The Exchange Email application must not share a partition with another application. 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 ot
    SV-84701r1_rule EX13-MB-000315 CCI-002385 MEDIUM Exchange must not send delivery reports to remote domains. Attackers can use automated messages to determine whether a user account is active, in the office, traveling, and so on. An attacker might use this information to conduct future attacks. Ensure that delivery reports to remote domains are disabled. Before
    SV-84703r1_rule EX13-MB-000320 CCI-002385 MEDIUM Exchange must not send nondelivery reports to remote domains. Attackers can use automated messages to determine whether a user account is active, in the office, traveling, and so on. An attacker might use this information to conduct future attacks. Ensure that nondelivery reports to remote domains are disabled. Befo