Title

Trust Bar Notifications for unsigned application add-ins must be blocked. (Cat II impact)

Discussion

If an application is configured to require all add-ins be signed by a trusted publisher, any unsigned add-ins the application loads will be disabled and the application will display the Trust Bar at the top of the active window. The Trust Bar contains a message informing users about the unsigned add-in.

Check Content

The policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2010 -> Excel Options -> Security -> Trust Center “Disable Trust Bar Notification for unsigned application add-ins and block them” must be “Enabled”. Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\14.0\excel\security Criteria: If the value NoTBPromptUnsignedAddin is REG_DWORD = 1, this is not a finding.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2010 -> Excel Options -> Security -> Trust Center “Disable Trust Bar Notification for unsigned application add-ins and block them” to “Enabled”.

Additional Identifiers

Rule ID: SV-33442r1_rule

Vulnerability ID: V-17187

Group Title: DTOO131 - Trust Bar Notifications

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.