Windows Server 2019 must not allow anonymous enumeration of Security Account Manager (SAM) accounts.

STIG ID: WN19-SO-000220 |  SRG: SRG-OS-000480-GPOS-00227 |  Severity: high |  CCI:  | Vulnerability Id: V-205914

Vulnerability Discussion

Anonymous enumeration of SAM accounts allows anonymous logon users (null session connections) to list all accounts names, thus providing a list of potential points to attack the system.

Check

Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Network access: Do not allow anonymous enumeration of SAM accounts" to "Enabled".

Fix

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: \SYSTEM\CurrentControlSet\Control\Lsa\

Value Name: RestrictAnonymousSAM

Value Type: REG_DWORD
Value: 0x00000001 (1)