STIGQter: STIG Summary: Microsoft Exchange 2019 Mailbox Server Security Technical Implementation Guide Version: 2 Release: 3 Benchmark Date: 02 Jul 2025:

Exchange message size restrictions must be controlled on send connectors.

DISA Rule

SV-259681r961155_rule

Vulnerability Number

V-259681

Group Title

SRG-APP-000247

Rule Version

EX19-MB-000128

Severity

CAT III

CCI(s)

• CCI-001095 - Manage capacity, bandwidth, or other redundancy to limit the effects of information flooding types of denial of service attacks.

Weight

10

Fix Recommendation

Update the EDSP to specify the "MaxMessageSize" value or verify that this information is documented by the organization.

Open the Exchange Management Shell and enter the following command:

Set-SendConnector -Identity <'IdentityName'> -MaxMessageSize <MaxSendSize>

Note: The <IdentityName> value must be in quotes.

or

Enter the value as identified by the EDSP that has obtained a signoff with risk acceptance.

Repeat the procedures for each Send connector.

Check Contents

Review the EDSP or document that contains this information.

Determine the maximum message send size.

Open the Exchange Management Shell and enter the following command:

Get-SendConnector | Select-Object -Property Name, Identity, MaxMessageSize

For each Send connector, 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 maximum message send size value documented in the EDSP, this is a finding.

Vulnerability Number

V-259681

Documentable

False

Rule Version

EX19-MB-000128

Severity Override Guidance

Review the EDSP or document that contains this information.

Determine the maximum message send size.

Open the Exchange Management Shell and enter the following command:

Get-SendConnector | Select-Object -Property Name, Identity, MaxMessageSize

For each Send connector, 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 maximum message send size value documented in the EDSP, this is a finding.

Check Content Reference

M

Target Key

5580