Title

The Terminal Server does not require secure RPC communication. (Cat II impact)

Discussion

Allowing unsecure RPC communication exposes the server to man in the middle attacks and data disclosure attacks. A man in the middle attack occurs when an intruder captures packets between a client and server and modifies them before allowing the packets to be exchanged. Usually the attacker will modify the information in the packets in an attempt to cause either the client or server to reveal sensitive information.

Check Content

If the following registry value doesn’t exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Subkey: \Software\Policies\Microsoft\Windows NT\Terminal Services\ Value Name: fEncryptRPCTraffic Type: REG_DWORD Value: 1

Fix Text

Configure the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Terminal Services -> Encryption and Security -> RPC Security Policy “Secure Server (Require Security)” to “Enabled”.

Additional Identifiers

Rule ID: SV-4447r1_rule

Vulnerability ID: V-4447

Group Title: TS/RDS - Secure RPC Connection.

Expert Comments

CCIs tied to check.

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