hunt-deserialization

Look for base64 strings starting with rO0A or hex bytes AC ED 00 05 in cookies and request bodies, which indicate Java serialized objects. Also check for Content-Type: application/x-java-serialized-object and endpoints like /wls-wsat/ or /invoker/.

First confirm unserialize() processes user input by injecting a test object and observing error changes. Then generate a gadget chain with phpggc, for example phpggc Laravel/RCE5 system id, and deliver it via the vulnerable parameter or cookie.

ysoserial generates Java deserialization gadget chains such as CommonsCollections that execute arbitrary commands when deserialized. You pipe its output, often base64-encoded, into the vulnerable parameter and confirm execution via an out-of-band callback.

Yes, blind deserialization is confirmed with out-of-band techniques. Payloads trigger DNS or HTTP requests to a collaborator host like interactsh, proving code execution even when the server returns no command output.

If an application calls pickle.loads on attacker-controlled data, defining a class with a __reduce__ method returning os.system achieves arbitrary command execution. The risk applies whenever untrusted input reaches pickle, not to safe serialization formats.

Deserialization flaws typically yield remote code execution with the server process's privileges and no prerequisite conditions. A single crafted object can execute OS commands, making impact equivalent to full application compromise.