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 requirement is applicable to domain-joined systems, for standalone 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
Value Type: REG_DWORD
Value: 0
Fix
This requirement is applicable to domain-joined systems, for standalone systems this is NA.
Configure the policy value for Computer Configuration >> Administrative Templates >> System >> Logon >> "Enumerate local users on domain-joined computers" to "Disabled".