An attacker could send a specifically crafted payload to the XML-RPC invocation script and trigger the unserialize() call on the what parameter in the openads.spc RPC method. Such vulnerability could be used to perform various types of attacks, e.g. exploit serialize-related PHP vulnerabilities or PHP object injection. It is possible, although unconfirmed, that the vulnerability has been used by some attackers in order to gain access to some Revive Adserver instances and deliver malware through them to third party websites. This vulnerability was addressed in version 4.2.0.
The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Revive_adserver | Revive-sas | * | 4.2.0 (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.