Title

The Windows SMB client is not enabled to perform SMB packet signing when possible. (Cat II impact)

Discussion

If this policy is enabled, it causes the Windows Server Message Block (SMB) client to perform SMB packet signing when communicating with an SMB server that is enabled or required to perform SMB packet signing.

Check Content

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 “Microsoft Network Client: Digitally sign communications (if server agrees)” 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\Services\LanmanWorkstation\Parameters\ Value Name: EnableSecuritySignature Value Type: REG_DWORD Value: 1

Fix Text

Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> “Microsoft Network Client: Digitally sign communications (if server agrees)” to “Enabled”.

Additional Identifiers

Rule ID: SV-1166r1_rule

Vulnerability ID: V-1166

Group Title: SMB Client Packet Signing (if server agrees)

Expert Comments

CCIs tied to check.

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