Blocking as default file block opening behavior must be enforced.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-26612	DTOO110 - Excel	SV-33872r1_rule	ECSC-1	Medium

Description
Users can open, view, or edit a large number of file types in Excel 2010. Some file types are safer than others, as some could allow malicious code to become active on user computers or the network. For this reason, disabling or not configuring this setting could allow malicious code to become active on user computers or the network.

STIG	Date
Microsoft Excel 2010	2011-09-29

Details

Check Text ( C-34205r1_chk )
The policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2010 -> Excel Options -> Security -> Trust Center -> File Block Settings “Set default file block behavior” must be “Enabled: Blocked files are not opened". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\14.0\excel\security\fileblock Criteria: If the value OpenInProtectedView is REG_DWORD = 0, this is not a finding.

Check Text ( C-34205r1_chk )

The policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2010 -> Excel Options -> Security -> Trust Center -> File Block Settings “Set default file block behavior” must be “Enabled: Blocked files are not opened".

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

HKCU\Software\Policies\Microsoft\Office\14.0\excel\security\fileblock

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

Fix Text (F-29899r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2010 -> Excel Options -> Security -> Trust Center -> File Block Settings “Set default file block behavior” to “Enabled: Blocked files are not opened".