The Export User Data plugin for WordPress is vulnerable to arbitrary file deletion due to insufficient file path validation in the unserialize function in all versions up to, and including, 2.2.6. This makes it possible for authenticated attackers, with subscriber-level access and above, to delete arbitrary files on the server, which can easily lead to remote code execution when the right file is deleted (such as wp-config.php). Successful exploitation requires an administrator to trigger a user data export while a subscriber-level (or higher) user has stored a crafted serialized XLSXWriter object payload as their display name.
Weakness
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Potential Mitigations
- Make fields transient to protect them from deserialization.
- An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.