CVE-2021-40153 : Security Advisory and Response

The CVE-2021-40153 vulnerability involves Squashfs-Tools 4.5. Attackers can write to locations outside of the destination directory due to insufficient filename validation during the unsquash process.

Understanding CVE-2021-40153

This section will delve into the details of the CVE-2021-40153 vulnerability.

What is CVE-2021-40153?

The vulnerability squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5 permits writing to locations outside the intended directory during unsquashfs due to unvalidated filenames.

The Impact of CVE-2021-40153

The vulnerability allows attackers to write to locations outside of the destination directory, leading to potential security breaches and unauthorized access.

Technical Details of CVE-2021-40153

This section will provide technical insights into the CVE-2021-40153 vulnerability.

Vulnerability Description

Vulnerability in squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5
Filename not validated for traversal outside the destination directory

Affected Systems and Versions

Vendor: n/a
Product: n/a
Versions Affected: n/a

Exploitation Mechanism

Unsquashfs uses the stored filename to create a new file
Lack of validation allows writing to locations beyond the intended directory

Mitigation and Prevention

This section focuses on the steps to mitigate and prevent exploitation of CVE-2021-40153.

Immediate Steps to Take

Update to the latest version of Squashfs-Tools
Implement file validation mechanisms to prevent traversal attacks

Long-Term Security Practices

Regularly monitor and audit file system activities
Conduct security training for developers on secure coding practices

Patching and Updates

Keep software and tools updated with the latest security patches
Follow vendor advisories and security alerts for any further updates