A vulnerability was found in EyouCMS 1.6.5. It has been declared as critical. This vulnerability affects unknown code of the file /login.php?m=admin&c=Field&a=channel_edit of the component Backend. The manipulation of the argument channel_id leads to deserialization. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-259612. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
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.