Details

This policy setting controls which message encryption formats Outlook can use. Outlook supports three formats for encrypting and signing messages: S/MIME, Exchange, and Fortezza. If you enable this policy setting, you can specify whether Outlook can use S/MIME (the default), Exchange, or Fortezza encryption, or any combination of any of these options. Users will not be able to change this configuration. If you disable or do not configure this policy setting, Outlook only uses S/MIME to encrypt and sign messages. If you disable this policy setting, users will not be able to change this configuration.

Solution

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security -> Cryptography ‘Message Formats’ to ‘Enabled (SMIME)’.

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_MS_Outlook_2016_V2R1_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Identification and Authentication.This control applies to the following type of system Windows.

References

• 800-53|IA-7
• CAT|II
• CCI|CCI-000803
• Rule-ID|SV-228453r508021_rule
• STIG-ID|DTOO260
• STIG-Legacy|SV-85851
• STIG-Legacy|V-71227
• Vuln-ID|V-228453

Source

• Tenable.com/audits