The system will be configured to use Safe DLL Search Mode.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-3479	3.088	SV-32348r1_rule	ECSC-1	Medium

Description
The default search behavior, when an application calls a function in a Dynamic Link Library (DLL), is to search the current directory followed by the directories contained in the systems path environment variable. An unauthorized DLL inserted into an applications working directory could allow malicious code to be run on the system. Creating the following registry key and setting the appropriate value forces the system to search the %Systemroot% for the DLL before searching the current directory or the rest of the path.

Description

The default search behavior, when an application calls a function in a Dynamic Link Library (DLL), is to search the current directory followed by the directories contained in the systems path environment variable. An unauthorized DLL inserted into an applications working directory could allow malicious code to be run on the system. Creating the following registry key and setting the appropriate value forces the system to search the %Systemroot% for the DLL before searching the current directory or the rest of the path.

STIG	Date
Windows Server 2008 R2 Domain Controller Security Technical Implementation Guide	2012-09-05

Details

Check Text ( C-221r1_chk )
Analyze the system using the Security Configuration and Analysis snap-in. Expand the Security Configuration and Analysis tree view. Navigate to Local Policies -> Security Options. If the value for “MSS: (SafeDllSearchMode) Enable Safe DLL search mode (recommended)” is not set to “Enabled”, then this is a finding. The policy referenced configures the following registry value: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \System\CurrentControlSet\Control\Session Manager\ Value Name: SafeDllSearchMode Value Type: REG_DWORD Value: 1

Check Text ( C-221r1_chk )

Analyze the system using the Security Configuration and Analysis snap-in.
Expand the Security Configuration and Analysis tree view.
Navigate to Local Policies -> Security Options.

If the value for “MSS: (SafeDllSearchMode) Enable Safe DLL search mode (recommended)” is not set to “Enabled”, then this is a finding.

The policy referenced configures the following registry value:

Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \System\CurrentControlSet\Control\Session Manager\

Value Name: SafeDllSearchMode

Value Type: REG_DWORD
Value: 1

Fix Text (F-5699r1_fix)
Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> “MSS: (SafeDllSearchMode) Enable Safe DLL search mode (recommended)” to “Enabled”.