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Websites & UI (frontend)48k · #2456

browser-extension-reverse

Allows the agent to analyze browser extensions. It investigates how they work to find information or security flaws.

What it does

This tool helps you understand how browser extensions (like those for Chrome or Firefox) work. It analyzes the extension's files to see what it can do, how it accesses information, and if there are any risks.

When to use it

  • ✓When you want to check if an extension you use is secure.
  • ✓When analyzing an extension for educational or security purposes, with permission.
  • ✓To understand how an extension saves or accesses passwords and data.

Example of what to ask your AI

“Analyze the 'Super Secure Extension' from website X to see if it accesses my passwords.”

Want more? Open the sections below.

How to use

The easiest way: copy the message below and paste it into Claude, ChatGPT, Cursor or any AI. It reads the skill and follows the instructions.

Skill link

https://github.com/sickn33/agentic-awesome-skills/blob/main/plugins/agentic-awesome-skills-claude/skills/browser-extension-reverse/SKILL.md

Ready-to-paste message

Use this skill to help me: https://github.com/sickn33/agentic-awesome-skills/blob/main/plugins/agentic-awesome-skills-claude/skills/browser-extension-reverse/SKILL.md Read the SKILL.md file at that link and follow its instructions for my task.
How it works

The tool examines the extension's files, like 'manifest.json', to list its permissions and the scripts it runs. It can also observe how the extension communicates with the browser and the internet.

Installation

Easiest way: copy the skill link and paste it into Claude, ChatGPT or Cursor asking it to follow the instructions.

In the terminal (Claude Code, Codex, Cursor), in your project folder:

npx skills add sickn33/agentic-awesome-skills --skill browser-extension-reverse

Or download just the file:

curl -L https://raw.githubusercontent.com/sickn33/agentic-awesome-skills/main/plugins/agentic-awesome-skills-claude/skills/browser-extension-reverse/SKILL.md -o SKILL.md
Technical content (original SKILL.md)

Original text by the author, straight from GitHub.

⚠️ AUTHORIZED USE ONLY This skill is for educational purposes or authorized security assessments only. You must have explicit, written permission from the system owner before using this tool. Misuse of this tool is illegal and strictly prohibited.

Mandatory confirmation gate Before running any command that probes, exploits, changes, persists on, extracts data from, or attempts credential access against a target:

  1. Ask the user to state the exact target URL, IP, account, or resource.
  2. Ask the user to confirm written authorization and the permitted scope.
  3. Show the exact command(s) and explain their expected effect.
  4. Wait for explicit confirmation in the current conversation.

Without that confirmation, remain read-only and provide defensive guidance only. Prefer a sandbox, disposable VM, or controlled lab.

Browser Extension Reverse Engineering

When to Use

  • Auditing a browser extension's behavior and permissions in an authorized review.
  • Investigating how an extension handles credentials or sensitive page data.

适用场景

  • Chrome/Edge MV2/MV3 扩展分析
  • Firefox 扩展
  • 恶意扩展 IOC、供应链扩展投毒调查
  • 扩展实现的签名/加密/代理逻辑还原

工作流

1. 包体

□ crx 解压 / 从 profile 取扩展目录
□ manifest.json:permissions、host_permissions、background、content_scripts
□ 评估过度权限(<all_urls>、webRequest、debugger)

2. 逻辑

□ service_worker / background 入口
□ content_script 注入点与世界(isolated)
□ chrome.storage / IndexedDB 密钥
□ 与 `js-reverse` 相同:Observe 网络与消息传递(runtime.sendMessage)

3. 动态

□ 开发者模式加载解压目录
□ chrome://extensions 检查错误
□ DevTools 附加 service worker
□ 必要时 Frida/浏览器 CDP(jshookmcp)

工具链

工具 用途
解压/jq manifest
Chrome DevTools worker 调试
js-reverse 工具链 深度 JS
YARA 恶意扩展规则

参考

  • references/extension-analysis.md
  • field-journal 扩展恢复相关条目
  • ../js-reverse/ ../malware-analysis/

路由上下文

上游: MASTER R30
下游: 复杂混淆 JS → js-reverse;投毒调查 → supply-chain / malware

任务完成自检

  • 是否列出权限面与入口脚本?
  • 是否还原关键数据流?
  • Checklist?

Limitations

  • Extension stores update frequently; findings can go stale.
  • Dynamic analysis requires a profile isolated from personal accounts.

Adapted from zhaoxuya520/reverse-skill (MIT).

FAQ

Do I need permission to use this tool?

Yes, it is crucial to have explicit, written permission from the system owner before using this tool for any analysis, especially if it involves data or access.

What are 'background workers' and 'content scripts'?

'Background workers' (or service workers) are scripts that run in the background, even when you're not actively using the extension. 'Content scripts' are scripts that run within the web pages you visit.

Can the tool find malicious extensions?

Yes, it can help investigate extensions that might be malicious or have been compromised by analyzing their behavior and permissions.

Details

Original description by the author

Authorized reverse engineering of Chrome/Firefox extensions: manifest analysis, background workers, content scripts, and extension-based credential or data-exposure research.

repo: sickn33/agentic-awesome-skills

Popularity

GitHub stars
48k
Ranking position
#2456
License
MIT
Updated
10/15/2026

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