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

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

DISA Rule

SV-228383r612748_rule

Vulnerability Number

V-228383

Group Title

SRG-APP-000247

Rule Version

EX16-MB-000360

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 "MaxRecipientsPerMessage" 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'> -MaxRecipientsPerMessage 5000

Note: The <IdentityName> value 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

Note: This requirement applies to IMAP4. IMAP Secure is not restricted and does not apply to this requirement.

Review the Email Domain Security Plan (EDSP) or document that contains this information.

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, evaluate the "MaxRecipientsPerMessage" value.

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-228383

Documentable

False

Rule Version

EX16-MB-000360

Severity Override Guidance

Note: This requirement applies to IMAP4. IMAP Secure is not restricted and does not apply to this requirement.

Review the Email Domain Security Plan (EDSP) or document that contains this information.

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, evaluate the "MaxRecipientsPerMessage" value.

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

4223

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