The ability to sign into Office365 must be disabled.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-228535	DTOO405	SV-228535r508020_rule		Medium

Description
Office 2013 can be configured to prompt users for credentials to Office365 using either their Microsoft Account or the user ID assigned by an organization for accessing Office 365. Access to Office 365 will not be permitted and only locally installed and configured Office installations will be used.

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

Details

Check Text ( C-30768r498883_chk )
Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Office 2013 >> Miscellaneous >> "Block signing into Office" is set to "Enabled: org ID only". Use the Windows Registry Editor to navigate to the following HKCU\Software\Policies\Microsoft\Office\15.0\common\signin If the value 'signinoptions' is REG_DWORD = 2, this is not a finding.

Fix Text (F-30753r498884_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Office 2013 -> Miscellaneous -> "Block signing into Office" to "Enabled: org ID only".