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Exchange internal Send connectors must require encryption.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-221262EX16-ED-000690SV-221262r961632_ruleCCI-002418high
Description
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 Transport Layer Security (TLS) will be able to send and receive mail within the domain. The use of secure communication prevents eavesdroppers from reading or modifying communications between mail clients and servers. While sensitive message bodies should be encrypted by the sender at the client, requiring a secure connection from server to server adds protection by encrypting the sender and recipient information that cannot be encrypted by the sender. Individually, channel security and encryption can be compromised by attackers. Used together, email becomes a more difficult target, and security is heightened. Failure to enable this feature gives eavesdroppers an opportunity to read or modify messages between servers.
STIGDate
Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide2024-12-06

Related Frameworks

1 mapping across 5 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 4 hops (4) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

CRY-01Use of Cryptographic Controls
1.00
CRY-03Transmission Confidentiality
1.00
CRY-04Transmission Integrity
1.00
DCH-01Data Protection
1.00
NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (29) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

AC-10Concurrent Session Control
1.00
AC-17(1)Monitoring and Control
1.00
AC-17(2)Protection of Confidentiality and Integrity Using Encryption
1.00
AC-18(1)Authentication and Encryption
1.00
AC-3Access Enforcement
1.00
CM-6Configuration Settings
1.00
CM-7Least Functionality
1.00
IA-11Re-authentication
1.00
IA-2(8)Access to Accounts — Replay Resistant
1.00
IA-2(9)Network Access to Non-privileged Accounts — Replay Resistant
1.00

+19 more (top 10 by confidence shown)

NIST 800-1710 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (1) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

3.13.8
1.00
CCI1 mapping
CCI-002418
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (1) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

PR.DS-02
1.00

Who does this work

8 NICE work roles and 7 EC-Council certifications.

This is an inference across published mappings, not a single claim by anyone. This check maps to a control, which maps to a Cybersecurity Framework outcome, which NIST assigns to the work roles below. EC-Council separately maps its certifications to those same roles.

A certification prepares someone for a role. It is not evidence that a holder is qualified, and neither NIST nor EC-Council has stated that any certification here addresses this check.

Work-role assignments published by NIST (NICE Framework Components 2.2.0 and the CSF 2.0 OLIR crosswalk). Certification mappings published by EC-Council.

Details

Check Text (C-221262r961632_chk)

Open the Exchange Management Shell and enter the following command: Get-SendConnector | Select Name, Identity, TlsDomain If the value of "TlsDomain" is not set to the value of the internal <'SMTP Domain'>, this is a finding. Get-SendConnector | Select Name, Identity, DomainSecureEnabled If the value of "DomainSecureEnabled" is not set to "True" and the SendConnector is not using a smarthost, this is a finding. If the value of "DomainSecureEnabled" is set to "False" and the send connector is using a smarthost, the value of “RequireTLS” must be set to “True”, and the value for “TlsAuthLevel” must be set to “DomainValidation”. If the send connector using a smarthost has a value for “RequireTLS” that is not set to “True”, this is a finding. If the send connector using a smarthost has a value for “TlsAuthLevel” that is not set to “DomainValidation”, this is a Finding.

Fix Text (F-22966r811178_fix)

Open the Exchange Management Shell and enter the following command: Set-SendConnector -Identity <'IdentityName'> -TlsDomain <'SMTP Domain'> Set-SendConnector -Identity <'ReceiveConnector'> -DomainSecureEnabled 'True' Note: The SMTP Domain is the internal SMTP domain within the organization. The following commands can be executed if smarthosts are used: Set-SendConnector <'IdentityName'> -RequireTLS $true -TlsAuthLevel $DomainValidation