| V-33560 | Medium | SMTP IP Allow List entries must be empty. | Email system availability depends in part on best practices strategies for setting tuning configurations. Careful tuning reduces the risk that system or network congestion will contribute to... |
| V-33567 | Medium | 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... |
| V-33566 | Medium | 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... |
| V-33620 | Medium | Email software must be monitored for change on INFOCON frequency schedule. | 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... |
| V-33592 | Medium | 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... |
| V-33569 | Medium | Internet facing receive connectors must offer TLS before using basic authentication. | Sending unencrypted email over the Internet increases the risk that messages can be intercepted or altered. Transport Layer Security (TLS) is designed to protect confidentiality and data integrity... |
| V-33568 | Medium | External Receive Connectors must be Domain Secure Enabled. | 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... |
| V-33558 | Medium | SMTP IP Allow List Connection Filter must be enabled. | Email system availability depends in part on best practices strategies for setting tuning configurations. Careful tuning reduces the risk that system or network congestion will contribute to... |
| V-33625 | Medium | 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... |
| V-33603 | Medium | Exchange must not send auto 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... |
| V-33601 | Medium | External/Internet bound automated response messages must be disabled. | SPAM originators, in an effort to refine mailing lists, sometimes use a technique where they monitor transmissions for automated bounce back messages, such as 'Out of Office' messages. Automated... |
| V-33606 | Medium | Email Diagnostic log level must be set to low or 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,... |
| V-33626 | Medium | 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... |
| V-33608 | Medium | The Send Fatal Errors to Microsoft 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. This setting enables an automated log... |
| V-33581 | Medium | Recipient filter must be enabled. | Email system availability depends in part on best practices strategies for setting tuning configurations. Careful tuning reduces the risk that system or network congestion will contribute to... |
| V-33629 | Medium | The current, approved service pack must be 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.
|
| V-33621 | Medium | 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... |
| V-33644 | Medium | Messages with blank senders must be rejected. | By performing filtering at the perimeter, up to 90% of SPAM, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the mail server... |
| V-33623 | Medium | 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... |
| V-33642 | Medium | Filtered messages must be archived. | By performing filtering at the perimeter, up to 90% of SPAM, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the mail server... |
| V-33643 | Medium | Messages with blank sender field must be filtered. | By performing filtering at the perimeter, up to 90% of SPAM, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the mail server... |
| V-33640 | Medium | Non-existent recipients must not be blocked. | SPAM originators, in an effort to refine mailing lists, sometimes use a technique where they first create fictitious names, and then monitor rejected emails for non-existent recipients.
Those... |
| V-33641 | Medium | Sender Filter must block accepted domains at the edge. | SPAM origination sites and other sources of suspected Email-borne malware have the ability to corrupt, compromise, or otherwise limit availability of Email servers. Limiting exposure to unfiltered... |
| V-33631 | Medium | Messages with malformed from address must be rejected. | Sender Identification (SID) is an email anti-spam sanitization process. Sender ID uses DNS MX record lookups to verify the SMTP sending server is authorized to send email for the originating... |
| V-60981 | Medium | Internal Send Connectors must use an authentication level | 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... |
| V-33576 | Medium | 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. Ensure... |
| V-33578 | Medium | Tarpitting interval must be set.
| Tarpitting is the practice of artificially delaying server responses for specific SMTP communication patterns that indicate high volumes of SPAM or other unwelcome messages. The intent of... |
| V-33556 | Medium | Sender Identification Framework must be enabled. | Email is only as secure as the recipient. When the recipient is an email server accepting inbound messages, authenticating the sender enables the receiver to better assess message quality and to... |
| V-33557 | Medium | SMTP Sender Filter must be enabled. | Email system availability depends in part on best practices strategies for setting tuning configurations. Careful tuning reduces the risk that system or network congestion will contribute to... |
| V-33616 | Medium | Exchange must not send Customer Experience reports to Microsoft. | 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... |
| V-33611 | Medium | Audit data must be protected 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... |
| V-33613 | Medium | 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... |
| V-33619 | Medium | 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... |
| V-33618 | Medium | 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... |
| V-33639 | Medium | Sender reputation filter must be enabled. | By performing filtering at the perimeter, up to 90% of SPAM, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the Mail server... |
| V-33638 | Medium | Sender reputation filter must identify SPAM block level. | By performing filtering at the perimeter, up to 90% of SPAM, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the mail server... |
| V-33598 | 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... |
| V-33599 | Medium | Exchange must not send non-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... |
| V-33596 | Medium | 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... |
| V-33632 | Medium | 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,... |
| V-33594 | Medium | Internet facing send Connectors must specify a Smart Host. | In the case of 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... |
| V-33637 | Medium | Attachment filtering must remove undesirable attachments by file type. | By performing filtering at the perimeter, up to 90 percent of spam, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the mail server... |
| V-33636 | Medium | SPAM evaluation filter must be enabled. | By performing filtering at the perimeter, up to 90% of SPAM, malware, and other undesirable messages may be eliminated from the transport message stream, preventing their entry into the Exchange... |
| V-33634 | Medium | 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, stating the... |
| V-33633 | Medium | Block list service provider must be identified. | Block List filtering is a sanitization process performed on email messages prior to their arrival at the destination mailbox. By performing this process at the email perimeter, threats can be... |
| V-33622 | Medium | Accepted domains must be configured. | Exchange may be configured to accept email for multiple domain names. This setting identifies the domains for which the server will accept mail. This check verifies the email server is not... |
| V-33590 | Medium | Internal Send Connectors must use Domain Security (Mutual Authentication TLS). | 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... |
| V-33563 | Low | Internet Receive Connector connections count must be set to default. | Email system availability depends in part on best practices strategies for setting tuning configurations. This configuration controls the maximum number of simultaneous inbound connections allowed... |
| V-33561 | Low | Message size restrictions must be controlled on Receive connectors. | Email system availability depends in part on best practices strategies for setting tuning configurations. For message size restrictions, multiple places exist to set or override inbound or... |
| V-33565 | Low | Receive Connector timeout must be limited. | Email system availability depends in part on best practices strategies for setting tuning. This configuration controls the number of idle minutes before the connection is dropped. It works in... |
| V-33627 | Low | Global outbound message size must be controlled. | Email system availability depends in part on best practices strategies for setting tuning configurations. Message size limits should be set to 10 megabytes at most, but often are smaller,... |
| V-33583 | Low | 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... |
| V-33587 | Low | Message size restrictions must be controlled on Send connectors. | Email system availability depends in part on best practices strategies for setting tuning configurations. For message size restrictions, multiple places exist to set or override inbound or... |
| V-33586 | Low | Send Connectors delivery retries must be controlled. | This setting controls the rate at which delivery attempts from the home domain are retried, user notifications are issued, and notes the expiration time when the message will be discarded.
If... |
| V-33589 | Low | Send Connector connections count must be limited. | This 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. ... |
| V-33572 | Low | Receive Connectors must control the number of recipients per message. | Email system availability depends in part on best practices strategies for setting tuning configurations.
This configuration controls the maximum number of recipients who will receive a copy of... |
| V-33574 | Low | Receive Connectors must control the number of recipients chunked on a single message. | Email system availability depends in part on best practices strategies for setting tuning configurations. For message size restrictions, multiple places exist to set or override inbound or... |
| V-33575 | Low | 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... |
| V-33579 | Low | Receive Connector Maximum Hop Count must be 60. | Email system availability depends in part on best practices strategies for setting tuning configurations. This setting controls the maximum number of hops (email servers traversed) a message may... |
| V-33635 | Low | Outbound Connection Limit per Domain Count must be controlled.
| Email system availability depends in part on best practices strategies for setting tuning configurations. This configuration controls the maximum number of simultaneous outbound connections from a... |
| V-33646 | Low | Outbound Connection Timeout must be 10 or less. | Email system availability depends in part on best practices strategies for setting tuning configurations. This configuration controls the number of idle minutes before the connection is dropped.... |
