A vulnerability classified as critical was found in PHPEMS 6.x/7.x/8.x/9.0. Affected by this vulnerability is an unknown functionality in the library lib/session.cls.php of the component Session Data Handler. The manipulation leads to deserialization. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The identifier VDB-247357 was assigned to this vulnerability.
The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Phpems | Phpems | 6.0 (including) | 6.0 (including) |
| Phpems | Phpems | 7.0 (including) | 7.0 (including) |
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.