# Browser Extension Reverse

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

- Skill: `francostino/browser-extension-reverse` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add francostino/browser-extension-reverse`
- Raw SKILL.md: https://api.skillmd.com/api/skills/francostino/browser-extension-reverse/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Research & Search
- License: MIT
- Author: FrancoStino (https://skillmd.com/u/francostino)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/francostino/browser-extension-reverse

---

> **⚠️ 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

```text
□ 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

```text
□ 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

```text
□ 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](https://github.com/zhaoxuya520/reverse-skill) (MIT).