Windows 11 systems must have Unified Extensible Firmware Interface (UEFI) firmware and be configured to run in UEFI mode, not Legacy BIOS.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-253256	WN11-00-000015	SV-253256r877465_rule		Medium

Description
UEFI provides additional security features in comparison to legacy BIOS firmware, including Secure Boot. UEFI is required to support additional security features in Windows 11, including virtualization-based Security and Credential Guard. Systems with UEFI that are operating in Legacy BIOS mode will not support these security features.

STIG	Date
Microsoft Windows 11 Security Technical Implementation Guide	2023-09-29

Details

Check Text ( C-56709r828850_chk )
For virtual desktop implementations (VDIs) where the virtual desktop instance is deleted or refreshed upon logoff, this is NA. Verify the system firmware is configured to run in UEFI mode, not Legacy BIOS. Run "System Information". Under "System Summary", if "BIOS Mode" does not display "UEFI", this is a finding.

Fix Text (F-56659r828851_fix)
Configure UEFI firmware to run in UEFI mode, not Legacy BIOS mode.