Blocking as default file block opening behavior must be enforced.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-70967	DTOO110	SV-85591r1_rule		Medium

Description
This policy setting allows you to determine if users can open, view, or edit Excel files. If you enable this policy setting, you can set one of these options:- Blocked files are not opened- Blocked files open in Protected View and can not be edited- Blocked files open in Protected View and can be edited. If you disable or do not configure this policy setting, the behavior is the same as the "Blocked files are not opened" setting. Users will not be able to open blocked files.

Description

This policy setting allows you to determine if users can open, view, or edit Excel files. If you enable this policy setting, you can set one of these options:- Blocked files are not opened- Blocked files open in Protected View and can not be edited- Blocked files open in Protected View and can be edited. If you disable or do not configure this policy setting, the behavior is the same as the "Blocked files are not opened" setting. Users will not be able to open blocked files.

STIG	Date
Microsoft Excel 2016 Security Technical Implementation Guide	2017-09-19

Details

Check Text ( C-71395r2_chk )
Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2016 -> Excel Options -> Security -> Trust Center -> File Block Settings "Set default file block behavior" is set to "Enabled: Blocked files are not opened". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\16.0\excel\security\fileblock Criteria: If the value OpenInProtectedView is REG_DWORD = 0, this is not a finding.

Check Text ( C-71395r2_chk )

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2016 -> Excel Options -> Security -> Trust Center -> File Block Settings "Set default file block behavior" is set to "Enabled: Blocked files are not opened".

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

HKCU\Software\Policies\Microsoft\Office\16.0\excel\security\fileblock

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

Fix Text (F-77299r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2016 -> Excel Options -> Security -> Trust Center -> File Block Settings "Set default file block behavior" to "Enabled: Blocked files are not opened".