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Exchange Message size restrictions must be controlled on Receive connectors.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-221231EX16-ED-000320SV-221231r961155_ruleCCI-001095low
Description
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 to control the maximum message size on Receive connectors. Using connectors to control size limits may necessitate applying message size limitations in multiple places, with the potential of introducing conflicts and impediments in the mail flow. Changing this setting at the connector overrides the global one. Therefore, if operational needs require it, the connector value may be set lower than the global value with the rationale documented in the EDSP.
STIGDate
Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide2024-12-06

Related Frameworks

1 mapping across 4 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (2) 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.

CAP-02Resource Priority
0.50
CAP-03Capacity Planning
0.50
NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (13) 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-17(10)Authenticate Remote Commands
1.00
AC-17(9)Disconnect or Disable Access
1.00
AC-3Access Enforcement
1.00
AC-4Information Flow Enforcement
1.00
AU-3Content of Audit Records
1.00
CM-6Configuration Settings
1.00
CM-7Least Functionality
1.00
CM-7(2)Prevent Program Execution
1.00
SC-47Alternate Communications Paths
1.00
SC-5Denial-of-service Protection
1.00

+3 more (top 10 by confidence shown)

CCI1 mapping
CCI-001095
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 4 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.IR-04
0.50

Details

Check Text (C-221231r961155_chk)

Review the Email Domain Security Plan (EDSP). Determine the global maximum message receive size. Open the Exchange Management Shell and enter the following command: Identify Internet-facing connectors. Get-ReceiveConnector | Select Name, Identity, MaxMessageSize If the value of "MaxMessageSize" is not the same as the global value, this is a finding. or If "MaxMessageSize" is set to a numeric value different from the global value and has signoff and risk acceptance in the EDSP, this is not a finding.

Fix Text (F-22935r411820_fix)

Update the EDSP to reflect the global maximum message receive size. Open the Exchange Management Shell and enter the following command: Set-ReceiveConnector -Identity <'IdentityName'> -MaxMessageSize <'MaxReceiveSize'> Note: The <IdentityName> and <MaxReceiveSize> values must be in single quotes. or The value as identified by the EDSP that has obtained a signoff with risk acceptance.