All network paths (UNCs) for Intranet sites must be disallowed.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-15504	DTBI375	SV-45079r1_rule		Medium

Description
Some UNC paths could refer to servers not managed by the organization, which means they could host malicious content; and therefore, it is safest to not include all UNC paths in the Intranet Sites zone. This policy setting controls whether URLs representing UNCs are mapped into the local Intranet security zone. If you enable this policy setting, all network paths are mapped into the Intranet Zone. If you disable this policy setting, network paths are not necessarily mapped into the Intranet Zone (other rules might map one there). If you do not configure this policy setting, users choose whether network paths are mapped into the Intranet Zone.

Description

Some UNC paths could refer to servers not managed by the organization, which means they could host malicious content; and therefore, it is safest to not include all UNC paths in the Intranet Sites zone. This policy setting controls whether URLs representing UNCs are mapped into the local Intranet security zone. If you enable this policy setting, all network paths are mapped into the Intranet Zone. If you disable this policy setting, network paths are not necessarily mapped into the Intranet Zone (other rules might map one there). If you do not configure this policy setting, users choose whether network paths are mapped into the Intranet Zone.

STIG	Date
Microsoft Internet Explorer 10 Security Technical Implementation Guide	2016-09-16

Details

Check Text ( C-42451r1_chk )
The policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Internet Explorer -> Internet Control Panel -> Security Page -> "Intranet Sites: Include all network paths (UNCs)" must be "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap Criteria: If the value UNCAsIntranet is REG_DWORD = 0, this is not a finding.

Check Text ( C-42451r1_chk )

The policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Internet Explorer -> Internet Control Panel -> Security Page -> "Intranet Sites: Include all network paths (UNCs)" must be "Disabled".

Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap

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

Fix Text (F-38486r1_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Internet Explorer -> Internet Control Panel -> Security Page -> "Intranet Sites: Include all network paths (UNCs)" to "Disabled".