Windows Server 2019 built-in guest account must be renamed.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-205910	SRG-OS-000480-GPOS-00227	WN19-SO-000040	SV-205910r991589_rule	2025-02-25	3

Description
The built-in guest account is a well-known user account on all Windows systems and, as initially installed, does not require a password. This can allow access to system resources by unauthorized users. Renaming this account to an unidentified name improves the protection of this account and the system.

ℹ️ 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: Rename guest account" is not set to a value other than "Guest", this is a finding. For server core installations, run the following command: Secedit /Export /Areas SecurityPolicy /CFG C:\Path\FileName.Txt If "NewGuestName" is not something other than "Guest" in the file, this is a finding.

ℹ️ 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: Rename guest account" is not set to a value other than "Guest", this is a finding. For server core installations, run the following command: Secedit /Export /Areas SecurityPolicy /CFG C:\Path\FileName.Txt If "NewGuestName" is not something other than "Guest" in the file, this is a finding.

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