External Signature Services Menu for Office must be suppressed.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-228521	DTOO204	SV-228521r508020_rule		Medium

Description
Users can select Add Signature Services (from the Signature Line drop-down menu on the Insert tab of the Ribbon in Excel 2013, PowerPoint 2013, and Word 2013) to see a list of signature service providers on the Microsoft Office website. If an organization has policies that govern the use of external resources such as signature providers or Office Marketplace, allowing users to access the Add Signature Services menu item might enable them to violate those policies.

Description

Users can select Add Signature Services (from the Signature Line drop-down menu on the Insert tab of the Ribbon in Excel 2013, PowerPoint 2013, and Word 2013) to see a list of signature service providers on the Microsoft Office website. If an organization has policies that govern the use of external resources such as signature providers or Office Marketplace, allowing users to access the Add Signature Services menu item might enable them to violate those policies.

STIG	Date
Microsoft Office System 2013 Security Technical Implementation Guide	2020-09-25

Details

Check Text ( C-30754r498841_chk )
Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Office 2013 >> Signing "Suppress external signature services menu item" is set to "Enabled". Use the Windows Registry Editor to navigate to the following HKCU\Software\Policies\Microsoft\Office\15.0\common\signatures Criteria: If the value 'SuppressExtSigningSvcs' is REG_DWORD = 1, this is not a finding.

Fix Text (F-30739r498842_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Office 2013 -> Signing "Suppress external signature services menu item" to "Enabled".