analyzing-binaries

analyzing-binaries is a skill for Claude Code, Codex from EvilFreelancer/secs. It costs 68 tokens per session (2,770 once invoked), scanned A, a copy of analyzing-binaries, Apache-2.0.

A workflow for reverse engineering compiled programs when their source code is unavailable. It examines executables, firmware, and mobile-app packages by narrowing the search, disassembling code, and observing behavior.

In plain words
What is it for?
Analyzing ELF, PE, and Mach-O files, embedded firmware, native mobile components, stripped binaries, and capture-the-flag reversing challenges.
Why use it?
It helps explain what unknown software does and recover details such as algorithms, file formats, communication protocols, or vulnerabilities.

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/evilfreelancer/secs/analyzing-binaries
Any agent
npx skills add EvilFreelancer/secs --skill analyzing-binaries
Clone the repo
git clone --depth 1 https://github.com/EvilFreelancer/secs

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 analyzing-binaries

README.md
[![agentmods](https://agentmods.dev/badge/skills/evilfreelancer/secs/analyzing-binaries.svg)](https://agentmods.dev/skills/evilfreelancer/secs/analyzing-binaries)
Your own site
<a href="https://agentmods.dev/skills/evilfreelancer/secs/analyzing-binaries"><img src="https://agentmods.dev/badge/skills/evilfreelancer/secs/analyzing-binaries.svg" alt="Measured on agentmods" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,770 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 86% copy Near-identical to another mod 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 $0.00068 $0.02770
Opus 5 $0.00034 $0.01385
Sonnet 5 $0.00014 $0.00554
Haiku 4.5 $0.00007 $0.00277

Measured 3d ago against content hash 5dfc745d6f0a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

analyzing-binaries 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.

Origin

This is a copy

86% identical to analyzing-binaries — 26 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/analyzing-binaries/SKILL.md · 251 lines

How it starts

The opening of the file, as written. The whole thing — 251 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Analyzing Binaries

Reverse engineering is hypothesis testing against a program you cannot read. The cost of the job is dominated by how much code you look at, so the whole discipline is about narrowing: triage first, find the interesting few percent, then read that carefully.

When to Use

  • Understanding what an unknown or undocumented executable does
  • Recovering an algorithm, file format, or wire protocol from a binary
  • Locating a vulnerability in a closed-source target
  • Firmware analysis for embedded and IoT devices
  • Reversing challenges in CTFs

When NOT to Use

  • Live malware with intent to detonate — use analyzing-malware, which covers containment and safe detonation. Come back here for the disassembly.
  • Source is available — use auditing-code-for-vulnerabilities
  • Android/iOS app assessment as a whole — use testing-mobile-applications; use this skill for the native .so/Mach-O components inside it Framework runtimes (Flutter libapp.so/Dart snapshots, Unity libil2cpp.so plus global-metadata.dat, React Native Hermes), language runtimes with their own symbol recovery (Go pclntab, Rust panic strings, .NET IL), raw shellcode, packed or protected executables, and whole firmware images are all in scope here — each just needs its runtime-specific toolchain (binwalk and filesystem carving for firmware, an unpacker/dumper for protected binaries) rather than a cold disassembler pass.

Triage First — Never Open a Disassembler Cold

Every minute here saves an hour in the decompiler.

file target && du -h target
# Architecture, endianness, PIE, stripped or not — all decide your tooling
readelf -hSd target        # ELF: headers, sections, dynamic deps
rabin2 -I target           # radare2's normalized summary of any format
objdump -p target          # PE/ELF imports and load config

# Protections tell you what the author expected
checksec --file=target     # NX, canary, RELRO, PIE, Fortify

# Strings, but read them for structure rather than skimming
strings -n 8 -t x target | less        # ASCII with offsets
strings -e l -n 8 target               # UTF-16LE, essential on Windows

Read the full file on GitHub · 251 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. 3d ago First seen · 251 lines · 68 tokens per session scan A 5dfc745d6f0a

Subscribe to this mod's changes

analyzing-binaries is a skill published in the GitHub repository EvilFreelancer/secs (10 stars, last pushed 25d ago), licensed Apache-2.0. It adds 68 tokens to every session and 2,770 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 86% identical to analyzing-binaries, differing in 26 lines, and is treated as a copy.

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