Determine whether to force encrypted macros to be scanned in open XML workbooks.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17473	DTOO142 - Excel	SV-18534r1_rule	ECSC-1	Medium

Description
When an Office Open XML document (Word, Excel, Powerpoint) is rights-managed or password-protected, any macros that are embedded in the document are encrypted along with the rest of the contents. By default, these encrypted macros will be disabled unless they are scanned by antivirus software immediately before being loaded. If this default configuration is modified, Office 2007 products will not require encrypted macros to be scanned before loading. They will be handled as specified by the Office 2007 System macro security settings, which can cause macro viruses to load undetected and lead to data loss or reduced application functionality.

Description

When an Office Open XML document (Word, Excel, Powerpoint) is rights-managed or password-protected, any macros that are embedded in the document are encrypted along with the rest of the contents. By default, these encrypted macros will be disabled unless they are scanned by antivirus software immediately before being loaded. If this default configuration is modified, Office 2007 products will not require encrypted macros to be scanned before loading. They will be handled as specified by the Office 2007 System macro security settings, which can cause macro viruses to load undetected and lead to data loss or reduced application functionality.

STIG	Date
Microsoft Excel 2007	2014-12-22

Details

Check Text ( C-18821r1_chk )
The policy value for User Configuration -> Administrative Templates -> Microsoft Office Excel 2007 -> Excel Options -> Security “Determine whether to force encrypted macros to be scanned in Microsoft Excel Open XML workbooks” will be set to “Disabled”. Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\12.0\Excel\Security Criteria: If the value ExcelBypassEncryptedMacroScan is REG_DWORD = 0, this is not a finding.

Check Text ( C-18821r1_chk )

The policy value for User Configuration -> Administrative Templates -> Microsoft Office Excel 2007 -> Excel Options -> Security “Determine whether to force encrypted macros to be scanned in Microsoft Excel Open XML workbooks” will be set to “Disabled”.

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

HKCU\Software\Policies\Microsoft\Office\12.0\Excel\Security

Criteria: If the value ExcelBypassEncryptedMacroScan is REG_DWORD = 0, this is not a finding.

Fix Text (F-17413r1_fix)
The policy value for User Configuration -> Administrative Templates -> Microsoft Office Excel 2007 -> Excel Options -> Security “Determine whether to force encrypted macros to be scanned in Microsoft Excel Open XML workbooks” will be set to “Disabled”.