Loading story…
Microsoft disclosed that researchers found multiple Windows Recovery Environment (WinRE) weaknesses that could let an attacker with physical access bypass BitLocker protections and recover data from encrypted devices. The issues affected how WinRE handled unprotected files on recovery and EFI volumes during BitLocker auto-unlock, and included a Trusted WIM Boot bypass via Boot.sdi manipulation, abuse of ReAgent.xml scheduled operations through tttracer.exe and SetupPlatform.exe, and a Boot Configuration Data (BCD) parsing flaw that enabled a full Push Button Reset exploit chain to decrypt the OS volume. Microsoft said the four vulnerabilities were patched in the July 2025 Patch Tuesday release.
The disclosure prompted renewed guidance from the UK NCSC, which said BitLocker deployments without a pre-boot PIN remain exposed to known and future bypass techniques, including the YellowKey method that also abused WinRE. NCSC said the recurring problem is partly architectural because BitLocker does not encrypt WinRE-related files, leaving a persistent recovery-environment attack surface, and recommended enabling TPM+PIN to block these attacks by requiring user authentication before WinRE can be used. Where PINs are impractical, it advised alternatives including BitLocker Network Unlock, startup keys with TPM, and conditional access controls, while Microsoft also pointed customers to the REVISE mitigation to reduce downgrade risk.
See affected versions and whether adversaries are exploiting it.
4 events from the most recent confirmed update back to the earliest known activity.
The UK NCSC published guidance recommending that organizations configure BitLocker with a pre-boot PIN, arguing that BitLocker without a PIN remains vulnerable to YellowKey and similar WinRE-based bypasses. The guidance also suggested alternatives such as Network Unlock, Startup Keys with TPM, and conditional access controls where PIN use is impractical.
Microsoft published the 'BitUnlocker: Leveraging Windows Recovery to Extract BitLocker Secrets' blog detailing the WinRE attack surface, the four patched vulnerabilities, and mitigations such as TPM+PIN and REVISE. The post explained how the flaws could let attackers with physical access bypass BitLocker auto-unlock protections.
Microsoft fixed four vulnerabilities affecting WinRE and BitLocker in the July 2025 Patch Tuesday release: CVE-2025-48804, CVE-2025-48800, CVE-2025-48003, and CVE-2025-48818. The issues covered Boot.sdi manipulation, two ReAgent.xml scheduled-operation abuses, and a BCD/Push Button Reset exploit chain.
Microsoft Security researchers first presented their 2025 research into Windows Recovery Environment attack surfaces affecting BitLocker at Black Hat USA 2025 and DEF CON 33. The research described multiple ways physical attackers could abuse WinRE behavior to bypass BitLocker protections.
Vulnerabilities, threat actors, malware, products, organizations, and breaches Mallory has linked to this story.
See whether adversaries are exploiting this yet, and where the affected versions run in your environment.
3 references tracked. Mallory keeps watching after this page renders.
cyberveille.ch
Open sourcencsc.gov.uk
Open sourcetechcommunity.microsoft.com
Open sourceMap indicators from this story to your assets and identify affected systems in minutes.
Every observed campaign, victim, and pivot linked to actors named in this story.
Malware, exploits, and IOCs connected to the activity described here.
YARA, Sigma, and Snort rules deployed to your SIEM as soon as they’re published.
Get matching new stories delivered to your team as they break — not the next morning.
Ask questions about this story and take action on the answers.
Other stories Mallory is tracking that overlap on entities, sources, or topic labels.
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 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
An anonymous researcher using the aliases **Nightmare-Eclipse** and **Chaotic Eclipse** publicly released details for two alleged Microsoft zero-days, **YellowKey** and **GreenPlasma**, adding to a string of earlier disclosures that included **BlueHammer**, **RedSun**, and **UnDefend**. YellowKey is described as a **BitLocker bypass** that requires physical access and a USB device, allowing an attacker to reboot into the Windows Recovery Environment (**WinRE**) and gain access to an encrypted drive; reporting said the technique was independently reproduced. Public materials claim the issue affects **Windows 11** and **Windows Server 2022/2025**, while **Windows 10** is not affected. GreenPlasma was disclosed as a **local privilege escalation** flaw that allegedly abuses `CTFMon` and Windows Object Manager section handling to obtain **SYSTEM** privileges, although reports said the released code still triggers a UAC prompt under default settings. Security experts warned that YellowKey could sharply raise the impact of laptop theft because BitLocker is often the final safeguard for stolen Windows devices; suggested mitigations include enabling a **BitLocker PIN** and locking firmware settings with a **BIOS password**, while no practical workaround for GreenPlasma was identified beyond a future vendor patch. Microsoft had not publicly responded to the two disclosures at the time of reporting, and prior proof-of-concept releases from the same researcher were reportedly later used in real-world attacks.
Jun 29, 2026