detecting-insecure-deserialization-vulnerabilities

detecting-insecure-deserialization-vulnerabilities is a skill for Claude Code, Codex from withcrux/agentHack-skills. It costs 62 tokens per session (1,747 once invoked), scanned A, original, no licence file.

A security-testing guide for finding insecure deserialization in Java, Python, and PHP applications. Deserialization is the process of turning stored data back into objects; when unsafe, crafted data can sometimes run commands on a server.

In plain words
What is it for?
Finding gadget chains, using the ysoserial testing tool, and checking applications for unsafe serialized-object handling.
Why use it?
It helps identify a vulnerability that may allow remote code execution, where an attacker makes a system run their code. The work is limited to isolated lab environments.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing.

Good fit Finding gadget chains, using the ysoserial testing tool, and checking applications for unsafe serialized-object handling.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/withcrux/agenthack-skills/detecting-insecure-deserialization-vulnerabilities
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.

Any agent
npx skills add withcrux/agentHack-skills --skill detecting-insecure-deserialization-vulnerabilities
Clone the repo
git clone --depth 1 https://github.com/withcrux/agentHack-skills

Made for: Claude Code, Codex.

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 detecting-insecure-deserialization-vulnerabilities

README.md
[![agentmods](https://agentmods.dev/badge/skills/withcrux/agenthack-skills/detecting-insecure-deserialization-vulnerabilities/github.svg)](https://agentmods.dev/skills/withcrux/agenthack-skills/detecting-insecure-deserialization-vulnerabilities)
Your own site
<a href="https://agentmods.dev/skills/withcrux/agenthack-skills/detecting-insecure-deserialization-vulnerabilities"><img src="https://agentmods.dev/badge/skills/withcrux/agenthack-skills/detecting-insecure-deserialization-vulnerabilities/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for detecting-insecure-deserialization-vulnerabilities

Your own site · 80×15
<a href="https://agentmods.dev/skills/withcrux/agenthack-skills/detecting-insecure-deserialization-vulnerabilities"><img src="https://agentmods.dev/badge/skills/withcrux/agenthack-skills/detecting-insecure-deserialization-vulnerabilities.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,747 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.00062 $0.01747
Opus 5 $0.00031 $0.00873
Sonnet 5 $0.00012 $0.00349
Haiku 4.5 $0.00006 $0.00175

Measured 10d ago against content hash d9c2d58deca3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

detecting-insecure-deserialization-vulnerabilities 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 10d 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.

curl -I http://target:80/ | grep -i "Set-Cookie"

Runs shell commandslowCapability

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

return (os.system, ("id > /tmp/output",))
skills/detecting-insecure-deserialization-vulnerabilities/SKILL.md · 200 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 10d ago First seen · 200 lines · 62 tokens per session scan A d9c2d58deca3

Subscribe to this mod's changes

detecting-insecure-deserialization-vulnerabilities is a skill published in the GitHub repository withcrux/agentHack-skills (5 stars, last pushed 5mo ago), with no licence file. It adds 62 tokens to every session and 1,747 once invoked, about $0.0003 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 2026-08-31.

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