Title

The system must be configured to meet the minimum session security requirement for NTLM SSP based clients. (Cat II impact)

Discussion

Microsoft has implemented a variety of security support providers for use with RPC sessions. All of the options must be enabled to ensure the maximum security level.

Check Content

Analyze the system using the Security Configuration and Analysis snap-in. (See "Performing Analysis with the Security Configuration and Analysis Snap-in" in the STIG Overview document.) Expand the Security Configuration and Analysis tree view. Navigate to Local Policies -> Security Options. If the value for "Network security: Minimum session security for NTLM SSP based (including secure RPC) clients" is not set to "Require NTLMv2 session security" and "Require 128-bit encryption", this is a finding. The policy referenced configures the following registry value: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \System\CurrentControlSet\Control\Lsa\MSV1_0\ Value Name: NTLMMinClientSec Value Type: REG_DWORD Value: 0x20080000 (537395200) "Require NTLMv2 session security" will prevent authentication, if the "Network security: LAN Manager Authentication level" is set to permit NTLM or LM authentication.

Fix Text

Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> "Network security: Minimum session security for NTLM SSP based (including secure RPC) clients" to "Require NTLMv2 session security" and "Require 128-bit encryption" (all options selected).

Additional Identifiers

Rule ID: SV-48084r1_rule

Vulnerability ID: V-3382

Group Title: Session Security for NTLM SSP Based Clients

Expert Comments

CCIs tied to check.

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