Integer Underflow in Dislocker Leading to Heap Read

Executive Summary

Dislocker through version 0.7.3 has an integer underflow flaw in the get_vmk() and get_fvek() functions. Attackers exploit this by providing a malicious BitLocker volume image with a datum_size smaller than the required 36-byte AES-CCM header. This causes hexdump() to read beyond allocated memory, leading to crashes or potential unauthorized access.

Useful 0 Not Useful 0

Detection Guidance

To detect this vulnerability, inspect Dislocker versions prior to 0.7.3 for crashes when processing BitLocker volume images with malformed datum sizes. Check for crashes in dislocker processes or FUSE mounts after exposing the system to crafted BitLocker images. Use version checks like 'dislocker -v' to identify vulnerable versions.

Useful 0 Not Useful 0

Impact Analysis

If exploited, this vulnerability could crash Dislocker, disrupting access to encrypted BitLocker volumes. While it does not directly expose data, crashes may lead to denial-of-service conditions or unexpected behavior during decryption processes.

Useful 0 Not Useful 0

Compliance Impact

This vulnerability may impact compliance by causing disruptions in data access, potentially violating availability requirements in GDPR or HIPAA. However, no direct data exposure is indicated, so confidentiality breaches are unlikely.

Useful 0 Not Useful 0

Mitigation Strategies

Update dislocker to version 0.7.4 or later to address the integer underflow vulnerability in get_vmk() and get_fvek(). Avoid processing untrusted BitLocker volume images until patched.

Useful 0 Not Useful 0