Information
This policy setting determines whether the Server Message Block (SMB) server will log events when the SMB client doesn't support signing.
Enabling this will create event log entries in Applications and Services Logs\Microsoft\Windows\SMBClient\Audit with Event ID 31999
The recommended state for this setting is: Enabled
Organizations should be aware of all unsigned SMB traffic in their environment. Older SMB protocols that do not use signing can make an environment susceptible to many types of attacks, including SMB interception attacks.
Solution
To establish the recommended configuration via GP, set the following UI path to Enabled :
Computer Configuration\Policies\Administrative Templates\Network\Lanman Server\Audit client does not support signing
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:
All SMB traffic that is unsigned will be logged as an event.