Title

The system must be configured to use Safe DLL Search Mode. (Cat II impact)

Discussion

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 system's path environment variable. An unauthorized DLL, inserted into an application's working directory, could allow malicious code to be run on the system. Setting this policy value forces the system to search the %Systemroot% for the DLL before searching the current directory or the rest of the path.

Check Content

If the following registry value does not exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \System\CurrentControlSet\Control\Session Manager\ Value Name: SafeDllSearchMode Value Type: REG_DWORD Value: 1

Fix Text

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". (See "Updating the Windows Security Options File" in the STIG Overview document if MSS settings are not visible in the system's policy tools.)

Additional Identifiers

Rule ID: SV-226309r794598_rule

Vulnerability ID: V-226309

Group Title: SRG-OS-000480-GPOS-00227

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.