Vulnerability Discussion

The username is one part of logon credentials that could be used to gain access to a system. Preventing the enumeration of users limits this information to authorized personnel.

Check

This applies to member servers. For domain controllers and standalone or nondomain-joined systems, this is NA.

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\System\

Value Name: EnumerateLocalUsers

Type: REG_DWORD
Value: 0x00000000 (0)

Fix

Configure the policy value for Computer Configuration >> Administrative Templates >> System >> Logon >> Enumerate local users on domain-joined computers to "Disabled".