pentest-ctf-binary

pentest-ctf-binary is a skill for Claude Code, Codex from jd-opensource/JoySafeter. It costs 26 tokens per session (207 once invoked), scanned A, original, Apache-2.0.

A guide to analyzing compiled programs for memory-safety bugs and creating exploits, mainly for capture-the-flag (CTF) challenges and software research.

In plain words
What is it for?
It is for inspecting binaries, debugging them, finding buffer overflows and related bugs, building test payloads, and exploiting challenge servers to retrieve flags.
Why use it?
It helps explain what a program does and investigate crashes or flaws that are not visible in its source code.

Skill for Claude CodeCodex

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/jd-opensource/joysafeter/pentest-ctf-binary
Any agent
npx skills add jd-opensource/JoySafeter --skill pentest-ctf-binary
Clone the repo
git clone --depth 1 https://github.com/jd-opensource/JoySafeter

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 pentest-ctf-binary

README.md
[![agentmods](https://agentmods.dev/badge/skills/jd-opensource/joysafeter/pentest-ctf-binary.svg)](https://agentmods.dev/skills/jd-opensource/joysafeter/pentest-ctf-binary)
Your own site
<a href="https://agentmods.dev/skills/jd-opensource/joysafeter/pentest-ctf-binary"><img src="https://agentmods.dev/badge/skills/jd-opensource/joysafeter/pentest-ctf-binary.svg" alt="Measured on agentmods" height="20"></a>
Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 207 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 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 $0.00026 $0.00207
Opus 5 $0.00013 $0.00103
Sonnet 5 $0.00005 $0.00041
Haiku 4.5 $0.00003 $0.00021

Measured 3d ago against content hash 1c8a2d6bc366, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

pentest-ctf-binary scanned grade A with 0 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 3d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/pentest-ctf-binary/SKILL.md · 21 lines

What it actually says

Pentest CTF Binary

Purpose

Analyze binary files to understand their behavior, identify memory corruption vulnerabilities, and develop exploits (ROP, Heap, Format String).

Core Workflow

  1. Static Analysis: Inspect binary properties, protections (NX, PIE), and code structure using checksec and ghidra.
  2. Dynamic Analysis: Run the binary under a debugger (gdb) to observe behavior and register states.
  3. Vulnerability Identification: Locate crashes, buffer overflows, or format string bugs.
  4. Exploit Development: Construct payloads (shellcode, ROP chains) using pwntools.
  5. Remote Exploitation: Launch the exploit against the target server to retrieve the flag.

References

  • references/tools.md
  • references/workflows.md
Files

What ships with it

2 files 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. 3d ago First seen · 21 lines · 26 tokens per session scan A 1c8a2d6bc366

Subscribe to this mod's changes

pentest-ctf-binary is a skill published in the GitHub repository jd-opensource/JoySafeter (305 stars, last pushed 7d ago), licensed Apache-2.0. It adds 26 tokens to every session and 207 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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