The unpack implementation in Swoole version 4.0.4 lacks correct size checks in the deserialization process. An attacker can craft a serialized object to exploit this vulnerability and cause a SEGV.
Weakness
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Swoole | Swoole | 4.0.4 (including) | 4.0.4 (including) |
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.
Related Attack Patterns
References
- https://github.com/swoole/swoole-src/commit/4cdbce5d9bf2fe596bb6acd7d6611f9e8c253a76
- https://github.com/swoole/swoole-src/issues/1882
- https://x-c3ll.github.io/posts/swoole-deserialization-cve-2018-15503/
- https://github.com/swoole/swoole-src/commit/4cdbce5d9bf2fe596bb6acd7d6611f9e8c253a76
- https://github.com/swoole/swoole-src/issues/1882
- https://x-c3ll.github.io/posts/swoole-deserialization-cve-2018-15503/