New GreatXML Exploit Bypasses Windows BitLocker via Recovery Partition XML Files

Security researcher Chaotic Eclipse (aka Nightmare-Eclipse and MSNightmare) has released a new Windows BitLocker bypass dubbed GreatXML, a day after they published an exploit for Microsoft Defender. "This was an accidental discovery, it took a total of 4 hours to find this," the researcher said in a post on Blogger. "If you ever attempted to use Windows Defender Offline Scan, you're

The article reports on GreatXML, a newly disclosed Windows BitLocker bypass where a crafted unattend.xml and modified Recovery directory placed on the recovery partition can, after Windows Defender Offline Scan has been used at least once, spawn a SYSTEM shell in WinRE with unrestricted access to BitLocker-encrypted volumes, without needing the password or key.[1][3][4][5] This is a local physical-access zero-day tied to Microsoft Defender Offline Scan and weak validation of configuration files in the Windows Recovery Environment, and full public proof-of-concept code has already been released.[4][5] From a CyberSE.AI perspective, while this is not an AI-model exploit, it materially increases endpoint compromise risk; any AI SaaS or agents whose secrets, tokens, or models are stored on affected Windows endpoints are more exposed to data theft and lateral movement if GreatXML is used. Organizations should harden BitLocker (e.g., TPM+PIN), restrict physical access, and include WinRE/BitLocker bypass scenarios in their AI security readiness planning to protect AI-related credentials, training data, and local model artifacts.