STIGQter: STIG Summary: Microsoft Exchange 2016 Mailbox Server Security Technical Implementation Guide Version: 2 Release: 3 Benchmark Date: 23 Apr 2021:

Exchange Message size restrictions must be controlled on Receive connectors.

DISA Rule

SV-228382r612748_rule

Vulnerability Number

V-228382

Group Title

SRG-APP-000247

Rule Version

EX16-MB-000350

Severity

CAT III

CCI(s)

• CCI-001095 - The information system manages excess 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 global maximum message receive size and, if operationally necessary, to document signoff with risk acceptance for the Receive connector to have a different value, or verify that this information is documented by the organization.

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

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

Repeat the procedure for each Receive connector.

Check Contents

Review the EDSP or document that contains this information.

Determine the global maximum message receive size and whether signoff with risk acceptance is documented for the Receive connector to have a different value.

Open the Exchange Management Shell and enter the following command:

Get-ReceiveConnector | Select Name, Identity, MaxMessageSize

Identify Internet-facing connectors.

For each Receive 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 global value and has signoff and risk acceptance in the EDSP, this is not a finding.

Vulnerability Number

V-228382

Documentable

False

Rule Version

EX16-MB-000350

Severity Override Guidance

Review the EDSP or document that contains this information.

Determine the global maximum message receive size and whether signoff with risk acceptance is documented for the Receive connector to have a different value.

Open the Exchange Management Shell and enter the following command:

Get-ReceiveConnector | Select Name, Identity, MaxMessageSize

Identify Internet-facing connectors.

For each Receive 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 global value and has signoff and risk acceptance in the EDSP, this is not a finding.

Check Content Reference

M

Target Key

4223

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