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VBA Macros not digitally signed must be blocked in Excel.


Overview

Finding ID Version Rule ID IA Controls Severity
V-223311 O365-EX-000002 SV-223311r811481_rule Medium
Description
This policy setting controls how the specified applications warn users when Visual Basic for Applications (VBA) macros are present. If you enable this policy setting, you can choose from four options for determining how the specified applications will warn the user about macros: - Disable all with notification: The application displays the Trust Bar for all macros, whether signed or unsigned. This option enforces the default configuration in Office. - Disable all except digitally signed macros: The application displays the Trust Bar for digitally signed macros, allowing users to enable them or leave them disabled. Any unsigned macros are disabled, and users are not notified. - Disable all without notification: The application disables all macros, whether signed or unsigned, and does not notify users. - Enable all macros (not recommended): All macros are enabled, whether signed or unsigned. This option can significantly reduce security by allowing dangerous code to run undetected.
STIG Date
Microsoft Office 365 ProPlus Security Technical Implementation Guide 2022-06-17

Details

Check Text ( C-24984r811480_chk )
Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Excel 2016 >> Application Settings >> Security >> Trust Center >> "VBA macro Notification Settings" is set to "Enabled" and "Disable all except digitally signed macros" from the Options.

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

HKCU\software\policies\Microsoft\office\16.0\excel\security

If the value vbawarnings is REG_DWORD = 3, this is not a finding. Values of REG_DWORD = 2 or 4 are also acceptable. If the registry key does not exist or the value is REG_DWORD =1, this is a finding.
Fix Text (F-24972r442153_fix)
Set the policy value for User Configuration >> Administrative Templates >> Microsoft Excel 2016 >> Application Settings >> Security >> Trust Center >> "VBA macro Notification Settings" to "Enabled" and "Disable all except digitally signed macros" from the Options.