The WordPress Infinite Scroll – Ajax Load More plugin for WordPress is vulnerable to deserialization of untrusted input via the alm_repeaters_export parameter in versions up to, and including 5.5.3. This makes it possible for unauthenticated users to call files using a PHAR wrapper, granted they can trick a site administrator into performing an action such as clicking on a link, that will deserialize 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 product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ajax_load_more | Connekthq | * | 5.5.4 (excluding) |
It is often convenient to serialize objects for communication or to save them for later use. However, deserialized data or code can often be modified without using the provided accessor functions if it does not use cryptography to protect itself. Furthermore, any cryptography would still be client-side security – which is a dangerous security assumption. Data that is untrusted can not be trusted to be well-formed. When developers place no restrictions on “gadget chains,” or series of instances and method invocations that can self-execute during the deserialization process (i.e., before the object is returned to the caller), it is sometimes possible for attackers to leverage them to perform unauthorized actions, like generating a shell.