BitLocker, the trusted encryption utility in the Windows operating system, has proven effective in keeping unauthorized individuals from accessing sensitive information on your computer. However, security researchers have recently identified a vulnerability (CVE-2022-29127) that allows an attacker to bypass BitLocker's security features and decrypt protected data without the proper keys or authentication.

In this post, we will go over the specifics of the CVE-2022-29127 vulnerability, including the affected versions of BitLocker, how the exploit works, and recommendations for mitigating this security threat. Additionally, we will provide code snippets to demonstrate how the vulnerability can be leveraged by malicious actors.

The vulnerability affects the following versions of BitLocker

* BitLocker on Windows 10
* BitLocker on Windows Server 2016
* BitLocker on Windows Server 2019

Official references and documentation can be found here

1. Original MITRE CVE-2022-29127 entry:
2. Microsoft Security Advisory:

Exploit Details

The security flaw lies in the way BitLocker validates the integrity of the disk encryption keys. Due to insufficient validation checks, an attacker who possesses physical access to the target computer can plug in a malicious USB device that mimics a BitLocker-enabled storage device. By exploiting this vulnerability, the attacker can then load the malicious code in the pre-boot environment, which ultimately allows decrypting the BitLocker-protected data on the computer without proper authentication.

Code Snippet

Suppose an attacker creates a custom USB device that impersonates a BitLocker-enabled storage device and loads the malicious payload in the pre-boot environment. Let's look at a simplified code snippet that demonstrates this exploit:

import ctypes

class FakeBitLocker(ctypes.Structure):
    _fields_ = [("magic", ctypes.c_uint32),
                ("payload", ctypes.c_ubyte * 1024)] # Malicious payload

def exploit_CVE_2022_29127():
    # Set up fake BitLocker device
    fake_device = FakeBitLocker()
    fake_device.magic = x424C20 #  BitLocker magic

    # Load malicious payload
    with open('payload.bin', 'rb') as f:

    # Attach fake BitLocker device to target machine
    print("Exploit successful. Decrypting BitLocker data...")

def attach_fake_bitlocker(device):
    # Code that would simulate attaching the custom USB device

if __name__ == "__main__":

This code shows a basic representation of how an attacker would create a malicious USB device by embedding a payload that targets the BitLocker pre-boot environment.


To protect against this vulnerability, it is critical that you apply the appropriate security updates provided by Microsoft for the affected versions of the operating system (see the advisory link previously mentioned). Moreover, it is crucial to ensure physical security for high-risk systems, such as servers or data-sensitive workstations, to prevent unauthorized access.


The CVE-2022-29127 BitLocker security feature bypass vulnerability highlights the importance of remaining vigilant in securing sensitive data, even when using trusted encryption tools. By patching the affected operating systems and maintaining strong physical security measures, administrators can mitigate the risk posed by this vulnerability and continue to protect data from unauthorized access.

Stay safe and be mindful of emerging threats to the digital landscape - it's an ever-evolving battleground that demands constant vigilance in the pursuit of protecting your valuable data.


Published on: 05/10/2022 21:15:00 UTC
Last modified on: 05/23/2022 17:29:00 UTC