| Finding ID |
Severity |
Title |
Description |
|
V-221262
|
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 communications between servers. With this feature enabled, only servers capable of supporting... |
|
V-221261
|
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. With this feature enabled, only clients capable of supporting secure communications... |
|
V-221259
|
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 applications to mitigate the impact of DoS attacks that have occurred or... |
|
V-221253
|
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 not have a built-in message filtering capability. DoD Enterprise Email (DEE) has... |
|
V-221270
|
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 is identified and eradicated.
Malicious code includes viruses, worms, trojan horses, and... |
|
V-221269
|
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, which may allow the unauthorized distribution of... |
|
V-221268
|
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, which may allow the unauthorized distribution of... |
|
V-221267
|
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 is identified and eradicated.
Applications providing this capability must be able to... |
|
V-221266
|
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 is identified and eradicated.
Applications providing this capability must be able to... |
|
V-221265
|
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 is identified and eradicated.
Malicious code includes viruses, worms, trojan horses, and... |
|
V-221264
|
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 is identified and eradicated.
Malicious code includes viruses, worms, trojan horses, and... |
|
V-221263
|
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 activities, or information system error handling must also be addressed. |
|
V-221260
|
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 communications between servers. With this feature enabled, only servers capable of supporting... |
|
V-221258
|
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 about the responding product. While useful to the connecting client, connection responses can... |
|
V-221257
|
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 other applications sharing the same security context. For example, an exploit... |
|
V-221256
|
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 outside queries, and servers become more secure as a result.
Exchange Server has role-based server... |
|
V-221255
|
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 securing the host and the applications, as it is the... |
|
V-221254
|
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 with user permissions are less likely to access more highly secured areas. |
|
V-221252
|
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 authentication techniques used in combination can be effective in reducing... |
|
V-221251
|
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 scale well in an enterprise environment. This risk may be mitigated by using... |
|
V-221250
|
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 definitions, rule sets, and algorithms.
Exchange 2016 provides both antispam and antimalware protection out of the... |
|
V-221249
|
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 definitions, rule sets, and algorithms.
Exchange 2016 provides both antispam and antimalware protection out of the... |
|
V-221248
|
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 evaluation can significantly reduce spam, phishing, and spoofed emails. Filters for messages from blank senders, known... |
|
V-221247
|
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 evaluation can significantly reduce spam, phishing, and spoofed emails. Filters for messages from blank senders, known... |
|
V-221246
|
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 evaluation can significantly reduce spam, phishing, and spoofed emails. Filters for messages from blank senders, known... |
|
V-221245
|
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 need to use an SMTP... |
|
V-221244
|
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 communication process for spam batches to reduce the cost effectiveness of sending spam... |
|
V-221243
|
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 evaluation can significantly reduce spam, phishing, and spoofed emails. Messages from blank senders, known spammers, or... |
|
V-221242
|
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 Sender ID risks that spam could be admitted into the email domain... |
|
V-221241
|
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 them to do harm.
Block List services (sometimes called Reputation... |
|
V-221240
|
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 vector for inbound email-borne spam and malware.
Spam Evaluation filters scan inbound email... |
|
V-221239
|
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 for different forms of attacks. By filtering undesirable attachments, a large percent... |
|
V-221238
|
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 that blocks messages according to many characteristics of the sender. Sender Reputation relies... |
|
V-221237
|
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 that blocks messages according to many characteristics of the sender. Sender Reputation relies... |
|
V-221236
|
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 mailings.
To prevent this disclosure of existing email accounts to... |
|
V-221235
|
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 impacts.
The Global Deny list blocks messages originating from specific sources. Most blacklist... |
|
V-221234
|
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 for inbound email-borne spam and malware.
As messages are filtered, it is... |
|
V-221233
|
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 fields) cannot be replied to. Messages formatted in this way may be... |
|
V-221232
|
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 fields) cannot be replied to. Messages formatted in this way may be... |
|
V-221229
|
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 throughput capacity and can enable the ability to optimize message delivery.... |
|
V-221226
|
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 Internet protocol implementation, the hop count limit prevents a message from... |
|
V-221221
|
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 Connections Count setting as a delivery tuning mechanism. If the limit is too low, connections... |
|
V-221220
|
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 Count setting.
Connections, once established, may incur delays in message transfer. The default of... |
|
V-221219
|
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 eavesdropping, interception, and alteration. This setting forces Exchange to offer TLS before using... |
|
V-221218
|
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 for communications between servers. With this feature enabled, only servers capable of supporting... |
|
V-221217
|
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 at multiple locations throughout the enterprise.
Failure to identify a... |
|
V-221216
|
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. |
|
V-221215
|
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 exploit of an application server vulnerability may well be logged by monitoring or... |
|
V-221214
|
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 available for modification by a malicious user can be altered to conceal... |
|
V-221213
|
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 available for modification by a malicious user can be altered to conceal... |
|
V-221212
|
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 the platform by providing additional attack vectors.
Applications are capable of providing a wide variety... |
|
V-221211
|
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 available for modification by a malicious user can be altered to conceal... |
|
V-221210
|
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 the platform by providing additional attack vectors.
Applications are capable of providing a wide variety... |
|
V-221209
|
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 thresholds are reached, better enabling them to react in a timely fashion.
This field... |
|
V-221208
|
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 default, connectivity logging is disabled. If events are not recorded, it... |
|
V-221207
|
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 managing the logs to prevent risk of disk capacity denial of service conditions.
Exchange... |
|
V-221206
|
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 for communications between servers. With this feature enabled, messages can be securely passed... |
|
V-221204
|
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. |
|
V-221203
|
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 control methods that do not rely solely on the possession of a certificate... |
|
V-221202
|
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.
Connections, once established, may incur delays in message transfer. If the timeout period... |
|
V-221231
|
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 strategy can result in loss of data or system availability.
This setting enables the administrator... |
|
V-221230
|
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 simultaneous inbound connections is 5000. If a limit is set too low, the connections pool may... |
|
V-221228
|
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 strategy can result in loss of data or system availability.
This setting enables the administrator... |
|
V-221227
|
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.
Collectively, connectors should account for all connections required for the overall email topology design.... |
|
V-221225
|
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.
Collectively, connectors should account for all connections required for the overall email topology design.... |
|
V-221224
|
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 generate network congestion. If they are too far apart, messages... |
|
V-221223
|
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 strategy can result in loss of data or system availability.
This setting enables the administrator... |
|
V-221222
|
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 limit is too high, some domains may use... |
