CVE-2021-22564 : Exploit Details and Defense Strategies

This article provides details about CVE-2021-22564, a vulnerability in libjxl that could lead to a heap-based buffer overflow.

Understanding CVE-2021-22564

CVE-2021-22564 is a vulnerability in libjxl, specifically affecting versions less than or equal to 0.6.0. The issue arises when processing certain JPEG XL images out of order, potentially leading to an out of bounds copy of image pixels.

What is CVE-2021-22564?

The vulnerability in libjxl can result in a heap-based buffer overflow when decoding JPEG XL images with specific characteristics. Processing these images out of order may trigger an out of bounds copy, posing a security risk to systems utilizing the affected versions.

The Impact of CVE-2021-22564

The impact of CVE-2021-22564 is rated as MEDIUM severity according to the CVSS v3.1 scoring. While the attack complexity is considered HIGH, the availability, confidentiality, and integrity impacts are rated as LOW. The vulnerability requires low privileges for exploitation and no user interaction.

Technical Details of CVE-2021-22564

CVE-2021-22564 involves a heap-based buffer overflow in libjxl that can occur when processing JPEG XL images in a particular order. This vulnerability stems from an out of bounds copy of image pixels in the heap memory, potentially leading to unauthorized access or system compromise.

Vulnerability Description

When certain valid JPEG XL images are processed out of order by libjxl, the decoder may perform an out of bounds copy of image pixels, creating a security risk for the affected systems.

Affected Systems and Versions

The vulnerability affects libjxl versions less than or equal to 0.6.0. Systems utilizing these versions are at risk of experiencing the heap-based buffer overflow when processing specific JPEG XL images.

Exploitation Mechanism

The vulnerability can be exploited in multi-threaded decoding environments with heavy thread load or when images contain groups in an arbitrary order in the file. Attackers could potentially trigger the out of bounds copy by processing the right or bottom edges of the image.

Mitigation and Prevention

To address CVE-2021-22564, it is recommended to upgrade libjxl to versions past 0.6.0 or apply the patch available at https://github.com/libjxl/libjxl/pull/775.

Immediate Steps to Take

Users and administrators should prioritize updating libjxl to a secure version to mitigate the risk of exploitation due to the heap-based buffer overflow vulnerability.

Long-Term Security Practices

Implementing secure coding practices, regular security assessments, and staying informed about software vulnerabilities can help prevent similar issues in the future.

Patching and Updates

Regularly monitor for security updates and patches from the libjxl project to ensure that the software is up-to-date with the latest security fixes.