Replies or forwards to signed/encrypted messages must be signed/encrypted.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-228475	SRG-APP-000516	DTOO317	SV-228475r508021_rule	2022-03-11	2

Description
This policy setting controls whether replies and forwards to signed/encrypted mail should also be signed/encrypted. If you enable this policy setting, signing/encryption will be turned on when replying/forwarding a signed or encrypted message, even if the user is not configured for SMIME. If you disable or do not configure this policy setting, signing/encryption is not enforced.

ℹ️ Check
Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security -> Cryptography "Replies or forwards to signed/encrypted messages are signed/encrypted" is set to "Enabled". 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 NoCheckOnSessionSecurity is REG_DWORD = 1, this is not a finding.

ℹ️ Check

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security -> Cryptography "Replies or forwards to signed/encrypted messages are signed/encrypted" is set to "Enabled". 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 NoCheckOnSessionSecurity is REG_DWORD = 1, this is not a finding.

✔️ Fix
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security -> Cryptography "Replies or forwards to signed/encrypted messages are signed/encrypted" to "Enabled".