Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide
Description
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]
Details
Version / Release: V2R3
Published: 2021-12-16
Updated At: 2022-04-06 01:06:26
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Findings
| Severity | Open | Not Reviewed | Not Applicable | Not a Finding |
|---|---|---|---|---|
| Overall | 0 | 0 | 0 | 0 |
| Low | 0 | 0 | 0 | 0 |
| Medium | 0 | 0 | 0 | 0 |
| High | 0 | 0 | 0 | 0 |
Drop CKL or SCAP (XCCDF) results here.
| Vuln | Rule | Version | CCI | Severity | Title | Description | Status | Finding Details | Comments |
|---|---|---|---|---|---|---|---|---|---|
| SV-221202r612603_rule | EX16-ED-000010 | CCI-000054 | MEDIUM | Exchange must limit the Receive connector timeout. | 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 conjunction with the Maximum Inbound Connections Count setting. | ||||
| SV-221203r612603_rule | EX16-ED-000020 | CCI-000213 | MEDIUM | Exchange servers must use approved DoD certificates. | To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., networks, web servers, and web portals) must be properly configured to incorporate access cont | ||||
| SV-221204r612603_rule | EX16-ED-000030 | CCI-001368 | MEDIUM | Exchange must have accepted domains 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 accepting email for unauthorized domains. | ||||
| SV-221205r612603_rule | EX16-ED-000040 | CCI-001368 | MEDIUM | Exchange must have auto-forwarding of email to remote domains 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 Automatic Forwards to remote domains are disabled, except for | ||||
| SV-221206r612603_rule | EX16-ED-000050 | CCI-001368 | MEDIUM | Exchange 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. Several controls work together to provide security between internal servers. This setting controls the authentication method used fo | ||||
| SV-221207r612603_rule | EX16-ED-000060 | 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-221208r612603_rule | EX16-ED-000070 | 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-221209r612603_rule | EX16-ED-000080 | 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-221210r612603_rule | EX16-ED-000090 | 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-221211r612603_rule | EX16-ED-000100 | CCI-000162 | MEDIUM | Exchange Audit data must be protected against unauthorized access (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-221212r612603_rule | EX16-ED-000110 | 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-221213r612603_rule | EX16-ED-000120 | CCI-000163 | MEDIUM | Exchange audit data must be protected against unauthorized access for modification. | 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-221214r612603_rule | EX16-ED-000130 | CCI-000164 | MEDIUM | Exchange audit data must be protected against unauthorized access for 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-221215r612603_rule | EX16-ED-000140 | 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-221216r612603_rule | EX16-ED-000150 | CCI-001749 | MEDIUM | The Exchange local machine policy must require signed scripts. | Scripts, especially those downloaded from untrusted locations, often provide a way for attackers to infiltrate a system. By setting machine policy to prevent unauthorized script executions, unanticipated system impacts can be avoided. | ||||
| SV-221217r612603_rule | EX16-ED-000160 | 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-221218r811174_rule | EX16-ED-000170 | 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. Several controls work together to provide security between internal servers. This setting controls the authentication method used fo | ||||
| SV-221219r612603_rule | EX16-ED-000180 | CCI-001184 | MEDIUM | Exchange Internet-facing Receive connectors must offer Transport Layer Security (TLS) before using basic authentication. | Sending unencrypted email over the Internet increases the risk that messages can be intercepted or altered. TLS is designed to protect confidentiality and data integrity by encrypting email messages between servers and thereby reducing the risk of eavesdr | ||||
| SV-221220r612603_rule | EX16-ED-000190 | CCI-001095 | MEDIUM | 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-221221r612603_rule | EX16-ED-000200 | CCI-001095 | MEDIUM | 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-221222r612603_rule | EX16-ED-000230 | CCI-001095 | LOW | Exchange 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. If the limit is too low, connections may be dropped. If the l | ||||
| SV-221223r612603_rule | EX16-ED-000240 | 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-221224r612603_rule | EX16-ED-000250 | 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-221225r612603_rule | EX16-ED-000260 | 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-221226r612603_rule | EX16-ED-000270 | CCI-001095 | MEDIUM | 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-221227r612603_rule | EX16-ED-000280 | 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-221228r612603_rule | EX16-ED-000290 | CCI-001095 | LOW | Exchange Receive connectors must control the number of recipients chunked on a single message. | 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-221229r612603_rule | EX16-ED-000300 | CCI-001095 | MEDIUM | 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-221230r612603_rule | EX16-ED-000310 | CCI-001095 | LOW | The Exchange Internet Receive connector connections count must be set to default. | Email system availability depends in part on best practice strategies for setting tuning configurations. This configuration controls the maximum number of simultaneous inbound connections allowed to the SMTP server. By default, the number of simultaneou | ||||
| SV-221231r612603_rule | EX16-ED-000320 | CCI-001095 | LOW | Exchange 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 outbound message size. Failure to control the configuration strate | ||||
| SV-221232r612603_rule | EX16-ED-000330 | CCI-001308 | MEDIUM | Exchange messages with a blank sender field must be rejected. | 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 environment. Anonymous email (messages with blank sender fie | ||||
| SV-221233r612603_rule | EX16-ED-000340 | CCI-001308 | MEDIUM | Exchange messages with a blank sender field must be filtered. | 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 environment. Anonymous email (messages with blank sender fie | ||||
| SV-221234r612603_rule | EX16-ED-000350 | CCI-001308 | MEDIUM | Exchange filtered messages must be archived. | 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 environment. This significantly reduces the attack vector fo | ||||
| SV-221235r612603_rule | EX16-ED-000360 | CCI-001308 | MEDIUM | The Exchange Sender filter must block unaccepted domains. | 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 inbound messages can reduce the risk of spam and malware i | ||||
| SV-221236r612603_rule | EX16-ED-000370 | CCI-001308 | MEDIUM | Exchange nonexistent 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 not rejected are deemed to exist and are used in future spam mai | ||||
| SV-221237r612603_rule | EX16-ED-000380 | CCI-001308 | MEDIUM | The Exchange Sender Reputation filter must be enabled. | 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 environment. Sender Reputation is antispam functionality tha | ||||
| SV-221238r612603_rule | EX16-ED-000390 | CCI-001308 | MEDIUM | The Exchange Sender Reputation filter must identify the spam block level. | 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 environment. Sender Reputation is antispam functionality tha | ||||
| SV-221239r612603_rule | EX16-ED-000400 | CCI-001308 | MEDIUM | Exchange 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 environment. Attachments are being used more frequently fo | ||||
| SV-221240r612603_rule | EX16-ED-000410 | CCI-001308 | MEDIUM | The Exchange Spam Evaluation filter must be enabled. | By performing filtering at the perimeter, up to 90 percent of spam, malware, and other undesirable messages may be eliminated from the transport message stream, preventing their entry into the Exchange environment. This significantly reduces the attack ve | ||||
| SV-221241r612603_rule | EX16-ED-000420 | CCI-001308 | MEDIUM | The Exchange 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 eliminated outside the enclave, where there is less risk for th | ||||
| SV-221242r612603_rule | EX16-ED-000430 | CCI-001308 | MEDIUM | Exchange messages with a malformed From address must be rejected. | Sender Identification (SID) is an email antispam sanitization process. Sender ID uses DNS MX record lookups to verify the Simple Mail Transfer Protocol (SMTP) sending server is authorized to send email for the originating domain. Failure to implement Se | ||||
| SV-221243r612603_rule | EX16-ED-000470 | CCI-001308 | MEDIUM | The Exchange Recipient filter must be enabled. | Email system availability depends in part on best practice strategies for setting tuning configurations. Careful tuning reduces the risk that system or network congestion will contribute to availability impacts. Filters that govern inbound email evaluat | ||||
| SV-221244r612603_rule | EX16-ED-000480 | CCI-001308 | MEDIUM | The Exchange tarpitting interval must be set. | Tarpitting is the practice of artificially delaying server responses for specific Simple Mail Transfer Protocol (SMTP) communication patterns that indicate high volumes of spam or other unwelcome messages. The intent of tarpitting is to slow down the comm | ||||
| SV-221245r612603_rule | EX16-ED-000490 | 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), it will n | ||||
| SV-221246r612603_rule | EX16-ED-000500 | CCI-001308 | MEDIUM | Exchange Simple Mail Transfer Protocol (SMTP) IP Allow List entries must be empty. | Email system availability depends in part on best practice strategies for setting tuning configurations. Careful tuning reduces the risk that system or network congestion will contribute to availability impacts. Filters that govern inbound email evaluat | ||||
| SV-221247r612603_rule | EX16-ED-000510 | CCI-001308 | MEDIUM | The Exchange Simple Mail Transfer Protocol (SMTP) IP Allow List Connection filter must be enabled. | Email system availability depends in part on best practice strategies for setting tuning configurations. Careful tuning reduces the risk that system or network congestion will contribute to availability impacts. Filters that govern inbound email evaluat | ||||
| SV-221248r612603_rule | EX16-ED-000520 | CCI-001308 | MEDIUM | The Exchange Simple Mail Transfer Protocol (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 availability impacts. Filters that govern inbound email evalua | ||||
| SV-221249r612603_rule | EX16-ED-000530 | 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. Spam protection mechanisms include, for example, signature d | ||||
| SV-221250r612603_rule | EX16-ED-000540 | 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. Spam protection mechanisms include, for example, signature d | ||||
| SV-221251r612603_rule | EX16-ED-000550 | 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-221252r612603_rule | EX16-ED-000560 | CCI-001308 | MEDIUM | Exchange 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 validate the sending domain as authentic. One or more authen | ||||
| SV-221253r811176_rule | EX16-ED-000570 | CCI-001308 | HIGH | Exchange must render hyperlinks from email sources from non-.mil domains as unclickable. | Active hyperlinks within an email are susceptible to attacks of malicious software or malware. The hyperlink could lead to a malware infection or redirect the website to another fraudulent website without the user's consent or knowledge. Exchange does n | ||||
| SV-221254r612603_rule | EX16-ED-000580 | 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-221255r612603_rule | EX16-ED-000590 | CCI-001813 | MEDIUM | The 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-221256r612603_rule | EX16-ED-000610 | 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-221257r612603_rule | EX16-ED-000620 | CCI-002530 | MEDIUM | Exchange software must be installed on a separate partition from the OS. | 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-221258r612603_rule | EX16-ED-000630 | 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-221259r612603_rule | EX16-ED-000660 | CCI-002418 | HIGH | Exchange must provide redundancy. | Denial of Service (DoS) is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. This requirement addresses the configuration of ap | ||||
| SV-221260r612603_rule | EX16-ED-000670 | CCI-002385 | MEDIUM | Exchange 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. Several controls work together to provide security between internal servers. This setting controls the encryption method used for co | ||||
| SV-221261r612603_rule | EX16-ED-000680 | CCI-002418 | HIGH | 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-221262r811179_rule | EX16-ED-000690 | CCI-002418 | HIGH | 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. Several controls work together to provide security between internal servers. This setting controls the encryption method used for co | ||||
| SV-221263r612603_rule | EX16-ED-000700 | CCI-002605 | MEDIUM | Exchange must have the most current, approved service pack installed. | The organization (including any contractor to the organization) must promptly install security-relevant software updates (e.g., patches, service packs, hot fixes). Flaws discovered during security assessments, continuous monitoring, incident response acti | ||||
| SV-221264r612603_rule | EX16-ED-000720 | CCI-001241 | MEDIUM | The application must configure malicious code protection mechanisms to perform periodic scans of the information system every seven days. | 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-221265r612603_rule | EX16-ED-000730 | CCI-001241 | MEDIUM | The application must configure malicious code protection mechanisms to perform periodic scans of the information system every seven days. | 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-221266r612603_rule | EX16-ED-000750 | CCI-001243 | MEDIUM | The application must be configured to block and quarantine malicious code upon detection, then send an immediate alert to appropriate individuals. | 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-221267r612603_rule | EX16-ED-000760 | CCI-001243 | MEDIUM | The application must be configured to block and quarantine malicious code upon detection, then send an immediate alert to appropriate individuals. | 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-221268r612603_rule | EX16-ED-002400 | CCI-001240 | MEDIUM | The application must update malicious code protection mechanisms whenever new releases are available in accordance with organizational configuration management policy and procedures. | Malicious code includes viruses, worms, trojan horses, and spyware. The code provides the ability for a malicious user to read from and write to files and folders on a computer's hard drive. Malicious code may also be able to run and attach programs, whic | ||||
| SV-221269r612603_rule | EX16-ED-002410 | CCI-001240 | MEDIUM | The application must update malicious code protection mechanisms whenever new releases are available in accordance with organizational configuration management policy and procedures. | Malicious code includes viruses, worms, trojan horses, and spyware. The code provides the ability for a malicious user to read from and write to files and folders on a computer's hard drive. Malicious code may also be able to run and attach programs, whic | ||||
| SV-221270r612603_rule | EX16-ED-003010 | 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 | ||||