STIGQter: STIG Summary: Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide Version: 2 Release: 2 Benchmark Date: 22 Jan 2021:

Exchange Receive connectors must control the number of recipients per message.

DISA Rule

SV-221229r612603_rule

Vulnerability Number

V-221229

Group Title

SRG-APP-000247

Rule Version

EX16-ED-000300

Severity

CAT II

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 reflect the Maximum Recipients per Message value.

Open the Exchange Management Shell and enter the following command:

Set-ReceiveConnector -Identity <'IdentityName'> -MaxRecipientsPerMessage 5000

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

or

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 Email Domain Security Plan (EDSP).

Determine the Maximum Recipients per Message value.

Open the Exchange Management Shell and enter the following command:

Get-ReceiveConnector | Select Name, Identity, MaxRecipientsPerMessage

For each receive connector, if the value of "MaxRecipientsPerMessage" is not set to "5000", this is a finding.

or

If the value of "MaxRecipientsPerMessage" is set to a value other than "5000" and has signoff and risk acceptance in the EDSP, this is not a finding.

Vulnerability Number

V-221229

Documentable

False

Rule Version

EX16-ED-000300

Severity Override Guidance

Review the Email Domain Security Plan (EDSP).

Determine the Maximum Recipients per Message value.

Open the Exchange Management Shell and enter the following command:

Get-ReceiveConnector | Select Name, Identity, MaxRecipientsPerMessage

For each receive connector, if the value of "MaxRecipientsPerMessage" is not set to "5000", this is a finding.

or

If the value of "MaxRecipientsPerMessage" is set to a value other than "5000" and has signoff and risk acceptance in the EDSP, this is not a finding.

Check Content Reference

M

Target Key

4079

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