Open files based on content, not file extension for restricted sites zone are not disabled.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-15524	DTBI470	SV-16371r1_rule	ECSC-1	Medium

Description
This policy setting allows you to manage MIME sniffing for file promotion from one type to another based on a MIME sniff. A MIME sniff is the recognition by Internet Explorer of the file type based on a bit signature. If you enable this policy setting, the MIME Sniffing Safety Feature will not apply in this zone. The security zone will run without the added layer of security provided by this feature. If you disable this policy setting, the actions that may be harmful cannot run; this Internet Explorer security feature will be turned on in this zone, as dictated by the feature control setting for the process. If you do not configure this policy setting, the MIME Sniffing Safety Feature will not apply in this zone.

Description

This policy setting allows you to manage MIME sniffing for file promotion from one type to another based on a MIME sniff. A MIME sniff is the recognition by Internet Explorer of the file type based on a bit signature. If you enable this policy setting, the MIME Sniffing Safety Feature will not apply in this zone. The security zone will run without the added layer of security provided by this feature. If you disable this policy setting, the actions that may be harmful cannot run; this Internet Explorer security feature will be turned on in this zone, as dictated by the feature control setting for the process. If you do not configure this policy setting, the MIME Sniffing Safety Feature will not apply in this zone.

STIG	Date
Microsoft IE Version 7	2013-09-30

Details

Check Text ( C-14548r1_chk )
The policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Internet Explorer -> Internet Control Panel -> Security Page -> Restricted Sites Zone -> "Open files based on content, not file extension" will be set to “Enabled” and "Disable" selected from down drop box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4 Criteria: If the value 2100 is REG_DWORD = 3, this is not a finding.

Check Text ( C-14548r1_chk )

The policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Internet Explorer -> Internet Control Panel -> Security Page -> Restricted Sites Zone -> "Open files based on content, not file extension" will be set to “Enabled” and "Disable" selected from down drop box.

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

HKLM\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4

Criteria: If the value 2100 is REG_DWORD = 3, this is not a finding.

Fix Text (F-15157r1_fix)
The policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Internet Explorer -> Internet Control Panel -> Security Page -> Restricted Sites Zone -> "Open files based on content, not file extension" will be set to “Enabled” and "Disable" selected from down drop box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4 Criteria: Set the value 2100 to REG_DWORD = 3.

Fix Text (F-15157r1_fix)