CVE-2024-53263: Git LFS Credential Retrieval Vulnerability

In this post, we are discussing a security vulnerability found in Git LFS, a popular extension that allows Git users to version large files. The vulnerability, tracked as CVE-2024-53263, exposes sensitive Git credentials due to improper handling of URL-encoded control characters in the host's URL. This issue affects all versions of Git LFS before v3.6.1.

The Exploit

The vulnerability occurs when Git LFS tries to request credentials from Git for a remote host. It passes certain portions of the host's URL to the git-credential(1) command without verifying whether any embedded line-ending control characters are present. Consequently, an attacker can insert URL-encoded control characters, such as line feed (LF) or carriage return (CR), into the URL and potentially retrieve a user's Git credentials.

Let's take a look at a code snippet that demonstrates this vulnerability

import urllib

def exploit(url):
    # Insert URL-encoded control characters (LF or CR) into the URL
    payload = "%A"  # LF
    attack_url = url.replace("/", payload + "/")
    return attack_url

target_url = "https://git.example.com/my/repo.git";
malicious_url = exploit(target_url)
print("Malicious URL:", malicious_url)

In this example, the exploit function replaces all occurrences of the forward slash (/) in the target URL with a line feed (%A) followed by the forward slash. This would cause Git LFS to pass the manipulated URL to the git-credential(1) command, possibly exposing Git credentials to the attacker.

Original References

The vulnerability was first reported and fixed by Git LFS maintainers in v3.6.1. You can find more information and the patch details in the official Git LFS release notes:

- Git LFS v3.6.1 release notes

Solution & Recommendations

To address this vulnerability in Git LFS, it is highly recommended to upgrade to version v3.6.1. The latest version contains a patch that resolves this credential retrieval issue:

- Git LFS v3.6.1

Unfortunately, there are no known workarounds for this vulnerability at this time. The best course of action is to upgrade Git LFS to v3.6.1 or a later version.

Conclusion

Security vulnerabilities such as CVE-2024-53263 highlight the importance of keeping software up-to-date to protect sensitive information. Users of Git LFS must be aware of the potential risks associated with unpatched versions and take appropriate measures by upgrading to the latest, patched version to avoid possible exploitation by attackers. Stay safe and happy coding!

Timeline

Published on: 01/14/2025 20:15:28 UTC
Last modified on: 01/23/2025 18:15:30 UTC