hunting-java-deserialization-gadget-chains SKILL.md skillA
hunting-java-deserialization-gadget-chains from unboundcompute/security-agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add unboundcompute/security-agent-skills/hunting-java-deserialization-gadget-chains@git:20260826.c45369bPins git:20260826.c45369b in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- unboundcompute/security-agent-skills
- Path
skills/hunting-java-deserialization-gadget-chains/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260826.c45369b, committed Aug 26, 2026
- Size
- 9,286 bytes
- Repository stars
- 26
- License
- MIT
Hunt Java deserialization that turns an untrusted byte stream into code execution: attacker-controlled data reaching readObject, an ObjectInputStream, or a framework endpoint that deserializes, with a gadget on the classpath whose readObject or finalizer drives a property-oriented chain to a dangerous call. Covers native serialization, JNDI lookups reached through deserialized objects, and framework entry points that accept a serialized object over HTTP, a message queue, a cache, or a cookie.…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Hunting Java deserialization gadget chains: when reading an object runs code Java native serialization was never a trust boundary, but it is treated as one every time a service accepts a serialized object from a client, a queue, a cache, or a cookie and calls `readObject`. The danger is not the deserialization call by itself; it is the combination of that call with a gadget, an already-present library class whose own `readObject`, `readResolve`, or finalizer performs a side effect an attacker can steer. Chained together, ordinary library classes reconstruct into a sequence that ends in a runtime command, a naming lookup, or a template evaluation. You find these by locating every place untrusted bytes reach a deserializer and then asking which reachable library versions on the classpath carry a chain that fires on reconstruction. ## When to use - A service reads serialized Java objects from a client, a message queue, a cache, a file, or a cookie. - Untrusted input reaches `readObject`, an `ObjectInputStream`, or a framework method that deserializes. - Reachable library versions on the classpath are known to carry a deserialization gadget. ## Scope check …
Read the whole file at its exact version.
How to install
mdr add unboundcompute/security-agent-skills/hunting-java-deserialization-gadget-chains@sha256:0da80d16deddfda6The line at the top of this page pins the label git:20260826.c45369b, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_pfoziwpa5r7wgrjh)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Aug 26, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (9286 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
unboundcompute/security-agent-skills · 26 stars · license MIT · pushed 2026-09-08 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_pfoziwpa5r7wgrjh GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/hunting-java-deserialization-gadget-chains GET https://markdownregistry.com/api/v1/blob/0da80d16deddfda6c1aa49afaa2ed6c4973a90f41b4be4e19554801cae07815e
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.