Title

Determine whether to force encrypted macros to be scanned in open XML workbooks. (Cat II impact)

Discussion

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.

Check Content

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

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”.

Additional Identifiers

Rule ID: SV-18534r1_rule

Vulnerability ID: V-17473

Group Title:

Expert Comments

CCIs tied to check.

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