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V-228456

CAT II (Medium)

Automatic sending s/Mime receipt requests must be disallowed.

Rule ID

SV-228456r961863_rule

STIG

Microsoft Outlook 2016 Security Technical Implementation Guide

Version

V2R4

CCIs

CCI-000366

Discussion

This policy setting controls how Outlook handles S/MIME receipt requests. If you enable this policy setting, you can choose from four options for handling S/MIME receipt requests in Outlook:- Open message if receipt can't be sent- Don't open message if receipt can't be sent- Always prompt before sending receipt- Never send S/MIME receipts. If you disable or do not configure this policy setting, when users open messages with attached receipt requests, Outlook prompts them to decide whether to send a receipt to the sender with information about the identity of the user who opened the message and the time it was opened. If Outlook cannot send the receipt, the user is still allowed to open the message.

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security -> Cryptography "S/MIME receipt requests behavior" is set to "Enabled (Never send S\MIME receipts)".

Procedure: Use the Windows Registry Editor to navigate to the following key: 

HKCU\Software\Policies\Microsoft\Office\16.0\outlook\security

Criteria: If the value RespondToReceiptRequests is REG_DWORD = 2, this is not a finding.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security -> Cryptography "S/MIME receipt requests behavior" to "Enabled (Never send S\MIME receipts)".