18.6.7.7 (L1) Ensure 'Set authentication rate limiter delay (milliseconds)' is set to 'Enabled: 2000' or more

Information

This policy settings configures the SMB server invalid authentication delay value in milliseconds.

The recommended state for this setting is: Enabled: 2000 or more.

Authentication rate limiter considerably reduces the risk of brute force attacks by implementing a 2-second delay (default) between each failed NTLM or PKU2U-based authentication attempt.

According to Microsoft

, if an attacker sends 300 brute force attempts per second from a client for 5 minutes which equals 90,000 passwords, the same number of attempts would now take 50 hours or more.

Solution

To establish the recommended configuration via GP, set the following UI path to Enabled: 2000 or more:

Computer Configuration\Policies\Administrative Templates\Network\Lanman Server\Set authentication rate limiter delay (milliseconds)

Note: This Group Policy path may not exist by default. It is provided by the Group Policy template LanmanServer.admx/adml that is included with the Microsoft Windows 11 Release 24H2 Administrative Templates (or newer).

Impact:

None - 2,000 milliseconds (2 seconds) is the default behavior.

See Also

https://workbench.cisecurity.org/benchmarks/21344

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7(20)

Plugin: Windows

Control ID: 0cb544f5b21022ad8b24dc8573a275f4df32d592edbf85c6705e0533ee62a918