TorrentPier PHP object injection in multiple components

Executive brief

TorrentPier, a BitTorrent tracker engine, is vulnerable to a critical security flaw that allows attackers to inject malicious data into the system. By exploiting how the application handles internal data objects, an attacker could potentially take full control of the server or read sensitive files. This could lead to a total compromise of the tracker service and its underlying database.

Technical details

TorrentPier versions 2.4.3 and earlier are vulnerable to PHP Deserialization of Untrusted Data (CWE-502). The application fails to properly validate or sanitize data before passing it to the PHP unserialize() function. An attacker can exploit this by submitting specially crafted serialized objects, potentially triggering 'POP chains' (Property Oriented Programming) within the application's codebase. Successful exploitation can result in arbitrary code execution (RCE) or unauthorized file system access. The vulnerability is addressed in version 2.4.4.

Affected products

• torrentpier torrentpier <= 2.4.3

Timeline

• 2024-07-13: disclosed: Initial report by PHP Secure team
• 2026-05-11: advisory: GitHub Advisory published
• 2026-05-11: patched: Version 2.4.4 released

References

• https://api.github.com/users/PhpSecure
• https://github.com/PhpSecure
• https://api.github.com/users/PhpSecure/gists%7B/gist_id%7D
• https://api.github.com/users/PhpSecure/repos
• https://avatars.githubusercontent.com/u/118765013?v=4
• https://api.github.com/users/PhpSecure/events%7B/privacy%7D