Detections
Analytics
1.13.2.7 Ensure 'S/MIME receipt requests behavior' is set to Enabled:Never send S/MIME receipts
Information
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. The recommended state for this setting is: Enabled:Never send S/MIME receipts.
Rationale:
Incoming signed or encrypted messages might include S/MIME receipt requests. S/MIME receipts provide confirmation that messages are received unaltered, and can include information about who opened the message and when it was opened.
By default, 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.
In some situations, allowing Outlook to automatically send receipt requests could cause sensitive information to be divulged to unauthorized people.
Solution
To implement the recommended configuration state, set the following Group Policy setting to Enabled.User Configuration\Administrative Templates\Microsoft Outlook 2016\Security\Cryptography\S/MIME receipt requests behavior
Then set the Handle messages with S/MIME receipt requests in the following manner: option to Never send S/MIME receipts.
Impact:
Configuring this setting to 'Never send S/MIME receipts' does not affect users' ability to open and read e-mail messages. However, people who send messages with attached receipt requests to users affected by this setting will not receive the requested S/MIME receipts, which could cause confusion. Consider educating users about this setting so that they can advise e-mail correspondents to not expect any receipts they request.
See Also
Item Details
Audit Name: CIS Microsoft Office Outlook 2016 v1.1.0 Level 1
Category: SYSTEM AND COMMUNICATIONS PROTECTION
References: 800-53|SC-8(1)
Plugin: Windows
Control ID: 2e0663c95d0fe39741b1802001d0379ba8a22e09c0d1842d3d9d74b0f7267a5c