Smush – Lazy Load Images, Optimize & Compress Images <= 3.0.0 - Authenticated PHAR Deserialization

The Smush – Lazy Load Images, Optimize & Compress Images plugin for WordPress is vulnerable to deserialization of untrusted input via the '$log_file' value in versions up to, and including 3.0.0. This makes it possible for authenticated attackers to call files using a PHAR wrapper that will deserialize the data and call arbitrary PHP Objects that can be used to perform a variety of malicious actions granted a POP chain is also present. It also requires that the attacker is successful in uploading a file with the serialized payload.

The attempt arrives as an ordinary request to Smush: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Smush 3.0.1 closes this, and updating the plugin is the step that ends it.

• Firewall
• Scanner
• Alerts