The built-in administrator account must be renamed.

STIG ID: WN10-SO-000020 |  SRG: SRG-OS-000480-GPOS-00227 |  Severity: medium |  CCI:  | Vulnerability Id: V-220911

Vulnerability Discussion

The built-in administrator account is a well-known account subject to attack. Renaming this account to an unidentified name improves the protection of this account and the system.

Check

Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Accounts: Rename administrator account" to a name other than "Administrator".

Fix

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: Rename administrator account" is set to "Administrator", this is a finding.