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Researchers disclosed a hardware attack that can bypass Microsoft BitLocker protections by intercepting communications with the Trusted Platform Module (TPM) during the boot process. The technique, demonstrated by Guillaume Quéré, targets devices protected with BitLocker and a PIN by probing motherboard traces and using a logic analyzer to capture key material exchanged at startup, including an encrypted intermediate key that can be used to recover the Volume Master Key and decrypt the drive.
The attack requires physical access to the device and the ability to disassemble it, rather than any remote code execution or software exploit. Microsoft documents BitLocker as a data-at-rest protection feature for Windows, but the reported bypass highlights that its security can be undermined when attackers can access hardware signals directly. Reported mitigations focus on operational controls rather than a Windows patch, including strong physical security, secure storage of devices, and proper wiping or destruction of drives and systems at end of life.
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3 events from the most recent confirmed update back to the earliest known activity.
The same report states there is no current Windows mitigation for this specific physical attack path and recommends physical security controls, secure device storage, and proper drive wiping or destruction at retirement.
A weekly summary reports research by Guillaume Quéré showing a hardware-based technique to bypass BitLocker PIN protection by intercepting TPM communications during boot. The attack requires physical access and device disassembly to capture key material that can ultimately be used to decrypt the drive.
Microsoft published documentation describing BitLocker as a Windows data protection feature for encrypting operating system drives, fixed drives, and removable drives. The reference provides product background but does not anchor a publication date for this documentation.
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Researchers detailed multiple attack paths that can defeat or weaken Microsoft BitLocker on systems using **TPM-only** unlock, showing that physical access remains enough to recover disk encryption keys or bypass pre-boot protections in common configurations. Neodyme revisited the **Bitpixie** technique tied to `CVE-2023-21563`, describing how attackers can downgrade the Windows Boot Manager, abuse a PXE soft-reboot path, and recover the Volume Master Key from memory without the user’s password. A follow-up analysis said Microsoft has struggled to fully close downgrade paths because Secure Boot revocation capacity is limited, older Microsoft-signed bootloaders remain broadly trusted, and stricter PCR bindings have caused recovery and compatibility problems in the field. Separate research from MDSec showed that Dell UEFI firmware can be modified offline at the SPI flash level to disable pre-boot DMA protections while leaving BIOS settings appearing unchanged, enabling follow-on DMA attacks against Windows 11 devices protected by TPM-only BitLocker and, in some cases, privilege escalation even on TPM+PIN systems when the PIN is known. A public GitHub project compiling BitLocker attack techniques further underscored the breadth of the issue, cataloging hardware and software methods ranging from TPM bus sniffing and fTPM glitching to bootloader, WinRE, and recovery-environment flaws across numerous CVEs. Across the disclosures, the consistent mitigation theme was to avoid relying on TPM-only unlock where possible, apply Microsoft’s Secure Boot certificate updates such as **KB5025885**, and require a **pre-boot PIN** to materially raise the bar for physical attackers.
Jul 24, 2026
Microsoft has published **CVE-2026-50661**, a **Windows BitLocker** security feature bypass caused by **`CWE-693: Protection Mechanism Failure`**. The flaw allows an unauthorized attacker with **physical access** to bypass BitLocker protections on affected Windows systems, including multiple supported builds of **Windows 10, Windows 11, Windows Server 2016, 2019, 2022, and 2025**, before Microsoft’s listed fixed versions. Microsoft scored the issue **CVSS 6.1 (Medium)** and released vendor advisory and patch information through MSRC. If exploited, the weakness could let an attacker recover the **Volume Master Key**, decrypt the full physical volume, and access sensitive data such as user files, system configuration, and active session tokens. The same access could enable offline tampering, including modifying binaries, changing registry hives, or planting persistent malware such as **bootkits** or malicious drivers before the device is returned to service. Reported mitigations include applying Microsoft’s updates, requiring a **pre-boot PIN** for BitLocker, and disabling the Windows Recovery Environment with: ```bash reagentc /disable ```
Jul 15, 2026
Microsoft said some **Windows Server 2025** devices may enter **BitLocker recovery** after installing the April 2026 `KB5082063` security update, affecting systems with a specific and discouraged BitLocker Group Policy tied to TPM platform validation, PCR7, and Secure Boot conditions during transition to the **2023-signed Windows Boot Manager**. The company said the recovery key prompt should typically appear only on the first restart, is preparing a fix, and advised administrators to remove the problematic policy before deployment or use **Known Issue Rollback**; the issue is mainly expected in enterprise-managed environments rather than personal devices. Separately, researchers disclosed **BitUnlocker**, a downgrade attack that can expose data on BitLocker-protected **Windows 11** systems in under five minutes with physical access by exploiting `CVE-2025-48804` in the Windows Recovery Environment. The attack works because Secure Boot may still trust older **Microsoft Windows PCA 2011**-signed boot managers, allowing a pre-patch `bootmgfw.efi` and modified WinRE chain to launch `cmd.exe` with the encrypted volume already mounted; systems using **TPM-only** BitLocker remain at risk unless organizations migrate trust to **Windows UEFI CA 2023** via `KB5025885` or require **TPM+PIN** pre-boot authentication.
Jun 29, 2026