Windows Server 2019 must restrict unauthenticated Remote Procedure Call (RPC) clients from connecting to the RPC server on domain-joined member servers and standalone or nondomain-joined systems.

STIG ID: WN19-MS-000040  |  SRG: SRG-OS-000379-GPOS-00164 | Severity: medium |  CCI: CCI-001967

Vulnerability Discussion

Unauthenticated RPC clients may allow anonymous access to sensitive information. Configuring RPC to restrict unauthenticated RPC clients from connecting to the RPC server will prevent anonymous connections.

Check

This applies to member servers and standalone or nondomain-joined systems. It is NA for domain controllers.

If the following registry value does not exist or is not configured as specified, this is a finding:

Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SOFTWARE\Policies\Microsoft\Windows NT\Rpc\

Value Name: RestrictRemoteClients

Type: REG_DWORD
Value: 0x00000001 (1)

Fix

Configure the policy value for Computer Configuration >> Administrative Templates >> System >> Remote Procedure Call >> "Restrict Unauthenticated RPC clients" to "Enabled" with "Authenticated" selected.
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