Read signed email as plain text must be enforced.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17771	DTOO215	SV-53868r1_rule		Medium

Description
Outlook can display email messages and other items in three formats: plain text, Rich Text Format (RTF), and HTML. By default, Outlook displays digitally signed email messages in the format they were received in.

STIG	Date
Microsoft Outlook 2013 STIG	2018-09-05

Details

Check Text ( C-47909r1_chk )
Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Outlook Options -> Preferences -> E-mail Options "Read signed e-mail as plain text" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\outlook\options\mail Criteria: If the value ReadSignedAsPlain is REG_DWORD = 1, this is not a finding.

Check Text ( C-47909r1_chk )

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Outlook Options -> Preferences -> E-mail Options "Read signed e-mail as plain text" is set to "Enabled".

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

HKCU\Software\Policies\Microsoft\Office\15.0\outlook\options\mail

Criteria: If the value ReadSignedAsPlain is REG_DWORD = 1, this is not a finding.

Fix Text (F-46773r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Outlook Options -> Preferences -> E-mail Options "Read signed e-mail as plain text" to "Enabled".