Vulnerability Discussion

The built-in administrator account is a well-known account subject to attack. It also provides no accountability to individual administrators on a system. It must be disabled to prevent its use.

Check

Verify the effective setting in Local Group Policy Editor.
Run "gpedit.msc".

Navigate to Local Computer Policy >> Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options.

If the value for "Accounts: Administrator account status" is not set to "Disabled", this is a finding.

Fix

Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Accounts: Administrator account status" to "Disabled".