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Get Started Free →jeremylongshore/detecting-insecure-deserialization
Scan a source tree for unsafe-by-default deserialization APIs: Python pickle.loads / cPickle / shelve / dill, Ruby Marshal.load / YAML.load (pre-3.1 default), Java ObjectInputStream.readObject, PHP unserialize, .NET BinaryFormatter / NetDataContractSerializer, Node.js node-serialize, JavaScript JSON.parse with reviver containing eval.
Passed 18 of 21 test cases with the skill, and 16 of 21 without it.
2 fixed17 passed either way3 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
One of 2 test cases the skill fixed. Same model, same prompt, with and without the skill.
Construct a CI pipeline shell command to run the deserialization scanner on `/workspace` while suppressing lower-priority issues and logging findings as JSON.
| Checked | Without skill | With skill |
|---|---|---|
| Invokes scan_deserialization.py with --min-severity high | Missed | Passed |
| Sets output format to JSON using --format json | Missed | Passed |
The instructions your model reads when the skill loads.
Insecure deserialization (CWE-502, OWASP A08:2021) is the highest-
severity injection class in many language stacks because it directly
maps to RCE. Pickle, Java serialization, PHP unserialize, and
BinaryFormatter all execute object-construction code during
deserialization. If that code includes __reduce__ /
readObject / __wakeup / OnDeserialization callbacks that
the attacker controls, the deserialization step IS code execution.
Most legitimate use cases have safer alternatives (JSON for data, YAML with safe-load, Protocol Buffers, Avro). The remaining cases need explicit type allow-lists and HMAC-signed payloads.
| Finding | Severity | Threshold | Affected control |
|---|---|---|---|
Python pickle.loads(...) | CRITICAL | always (untrusted input) | CWE-502 |
Python pickle.load(file) | CRITICAL | always | CWE-502 |
Python dill.loads | CRITICAL | always | CWE-502 |
Python yaml.load(...) without Loader= | CRITICAL | unsafe legacy default | CWE-502 |
Python yaml.unsafe_load(...) | CRITICAL | explicit unsafe | CWE-502 |
Python shelve.open(...) | HIGH | pickle-backed; user-controllable filename | CWE-502 |
Java ObjectInputStream.readObject() | CRITICAL | always | CWE-502 |
PHP unserialize($input) | CRITICAL | non-literal input | CWE-502 |
.NET BinaryFormatter.Deserialize(...) | CRITICAL | deprecated unsafe API | CWE-502 |
.NET NetDataContractSerializer | CRITICAL | also unsafe | CWE-502 |
.NET LosFormatter.Deserialize | CRITICAL | ViewState path | CWE-502 |
Ruby Marshal.load(...) | CRITICAL | non-literal | CWE-502 |
Ruby YAML.load(...) (pre-3.1 Psych) | CRITICAL | safe in Psych 4.0+; needs version check | CWE-502 |
Node.js node-serialize.unserialize | CRITICAL | known-vulnerable lib | CWE-502 |
Node.js serialize-javascript reviver | HIGH | if used to deserialize untrusted | CWE-502 |
test cases passed, vs 16 / 21 without
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