hackbrowser-mcp

<p align="center"> <br> <picture> <source media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/badchars/hackbrowser-mcp/main/.github/banner-dark.svg"> <source media="(prefers-color-scheme: light)" srcset="https://raw.githubusercontent.com/badchars/hackbrowser-mcp/main/.github/banner-light.svg"> <img alt="hackbrowser-mcp" src="https://raw.githubusercontent.com/badchars/hackbrowser-mcp/main/.github/banner-dark.svg" width="700"> </picture> </p>

<h3 align="center">The first browser MCP built for security testing.</h3>

<p align="center"> Other browser MCPs let your AI fill forms and take screenshots.<br> This one lets it <b>find vulnerabilities</b>. </p>

<br>

<p align="center"> <a href="#what-it-does">What It Does</a> • <a href="#how-its-different">How It's Different</a> • <a href="#quick-start">Quick Start</a> • <a href="#workflow-examples">Examples</a> • <a href="#tools-reference-39-tools">Tools</a> • <a href="#architecture">Architecture</a> </p>

<p align="center"> <a href="LICENSE"><img src="https://img.shields.io/badge/license-MIT-blue.svg" alt="License"></a> <img src="https://img.shields.io/badge/runtime-Bun-f472b6" alt="Bun"> <img src="https://img.shields.io/badge/browser-Firefox-ff7139" alt="Firefox"> <img src="https://img.shields.io/badge/protocol-MCP-8b5cf6" alt="MCP"> <img src="https://img.shields.io/badge/tools-39-22c55e" alt="39 Tools"> <img src="https://img.shields.io/badge/injection%20payloads-60%2B-ef4444" alt="60+ Payloads"> </p>

---

What It Does

hackbrowser-mcp gives your AI agent a real Firefox browser and 39 security testing tools via the Model Context Protocol. The agent can launch the browser, browse a target, capture all traffic, and test for vulnerabilities — all through natural language.

You: "Log in as admin and as a regular user. Find endpoints the user shouldn't access."

Agent: → launches Firefox
       → creates two isolated containers (admin + user)
       → logs in both accounts
       → browses the app, captures traffic
       → compares responses across roles
       → "User can access GET /api/admin/users — should return 403, returns 200"

The AI handles the entire workflow: launching the browser, managing sessions, discovering endpoints, testing parameters, and generating a security report. You describe what to test. It does the rest.

---

How It's Different

There are dozens of browser MCPs. They all do the same thing: let an LLM navigate pages, click buttons, and extract text. They're built for automation — filling forms, scraping data, running UI tests.

None of them can test for vulnerabilities. That's the gap hackbrowser-mcp fills.

<table> <thead> <tr> <th></th> <th>Other Browser MCPs</th> <th>hackbrowser-mcp</th> </tr> </thead> <tbody> <tr> <td><b>Purpose</b></td> <td>Web automation, scraping, form filling</td> <td>Security testing, vulnerability assessment</td> </tr> <tr> <td><b>Sessions</b></td> <td>Single session</td> <td>2-4 isolated containers with separate cookies, storage, and auth</td> </tr> <tr> <td><b>Traffic</b></td> <td>Read-only network tab (if any)</td> <td>Full HAR capture + replay with modifications</td> </tr> <tr> <td><b>Security tools</b></td> <td>None</td> <td>14 tools: injection testing, CSRF, IDOR, access matrix, report generation</td> </tr> <tr> <td><b>Injection testing</b></td> <td>Not possible</td> <td>7 types, 60+ payloads, technique-labeled results</td> </tr> <tr> <td><b>Access control</b></td> <td>Not possible</td> <td>Cross-role comparison, endpoint access matrix, IDOR detection</td> </tr> <tr> <td><b>Browser</b></td> <td>Chromium (CDP)</td> <td>Firefox (WebDriver BiDi) — different engine catches different bugs</td> </tr> <tr> <td><b>Anti-detection</b></td> <td>Varies</td> <td>Stealth mode built-in (fingerprint, UA, WebGL spoofing)</td> </tr> </tbody> </table>

<br>

<details> <summary>Specific comparisons with popular projects</summary>

<br>

Project	Stars	What it does	What it can't do
playwright-mcp	29k	Navigate, click, type, screenshot via accessibility tree	No multi-session, no traffic capture, no security testing
browser-use	81k	AI completes web tasks (shopping, forms, research)	Single agent action, no HAR, no injection testing
stagehand	22k	act/extract/observe SDK for browser automation	No security tools, no container isolation
chrome-devtools-mcp	29k	DevTools debugging, performance analysis, network monitoring	Read-only network, no replay, no active testing
browser-tools-mcp	7k	Console, network, audit monitoring for coding agents	IDE-focused, no offensive testing capability
mcp-playwright	5k	Multi-browser test automation + scraping	No security awareness, no access control analysis

All of these are excellent tools for their intended purpose. hackbrowser-mcp doesn't replace them — it serves a completely different use case.

</details>

---

Core Capabilities

Multi-Container Isolation

Run 2-4 browser sessions simultaneously, each with completely isolated state. This is the foundation for access control testing.

┌────────────────────────────────────────────────────────┐
│                     Firefox Instance                    │
├───────────────┬───────────────┬────────────────────────-┤
│  Container 1  │  Container 2  │  Container 3            │
│  role: admin  │  role: user   │  role: guest             │
│               │               │                         │
│  cookies: A   │  cookies: B   │  cookies: none          │
│  storage: A   │  storage: B   │  storage: none          │
│  session: ✓   │  session: ✓   │  session: ✗             │
└───────────────┴───────────────┴─────────────────────────┘

compare_access → "GET /api/admin/users returns 200 for user (expected 403)"
access_matrix  → role × endpoint grid showing every authorization gap

Traffic Intelligence

Every HTTP request and response is captured, stored, and queryable. Replay any request with modifications.

Browser → Network Interceptor → In-Memory Store (10K max, FIFO)
                                       │
                             ┌─────────┴──────────┐
                             │                     │
                       Auto-save (60s)       Replay / modify
                             │                     │
                             ▼                     ▼
                       HAR file (disk)      replay_request
                             │              (change method,
                       Resume on restart     headers, body)

Active Security Testing

Discover injection points from captured traffic, then test them with 60+ payloads across 7 vulnerability types.

Type	Payloads	Techniques
SQLi	9	Error-based, union, time-based blind (MSSQL/MySQL/Postgres), boolean-blind
XSS	8	Reflected script, event handler, SVG, JS context, HTML5 events, iframe
SSTI	8	Jinja2, Freemarker, ERB, Angular sandbox, Spring EL, Vue
SSRF	8	Localhost variants (IPv4/v6/hex/octal), AWS/GCP/Azure metadata, DNS rebind
CMDi	8	Semicolon, pipe, backtick, subshell, newline, quote-break
LFI	8	Path traversal, double-dot, /proc/environ, PHP filter, double-encode
HTML Injection	6	Tag injection, form injection, style overlay, meta redirect

When built-in payloads get blocked, the AI agent analyzes the WAF response and crafts custom bypass payloads using replay_request.

---

Quick Start

Install

git clone https://github.com/user/hackbrowser-mcp.git
cd hackbrowser-mcp
bun install

Connect to your AI agent

<details> <summary><b>Claude Desktop / Claude Code</b></summary>

Add to your MCP config (~/.claude/claude_desktop_config.json):

{
  "mcpServers": {
    "hackbrowser": {
      "command": "bun",
      "args": ["run", "/path/to/hackbrowser-mcp/src/index.ts", "--mcp"]
    }
  }
}

</details>

<details> <summary><b>Cursor / Continue / other MCP clients</b></summary>

Same config format. Point the command to your installation path.

</details>

<details> <summary><b>Standalone (no AI agent)</b></summary>

bun run src/index.ts --launch              # GUI mode
bun run src/index.ts --launch --headless   # headless
bun run src/index.ts --mcp                 # MCP server (stdio)

</details>

Start testing

You: "Launch the browser and scan https://target.com for vulnerabilities"

That's it. The agent handles the rest.

---

Workflow Examples

Full Security Scan

You: "Crawl https://app.com, find injection points, test them, generate a report."

Agent: browser_launch → navigate → crawl (100 pages)
       → find_injection_points → test_injection (SQLi, XSS)
       → test_csrf → test_rate_limit
       → generate_report
       → "Found 3 XSS, 1 SQLi, 2 missing CSRF tokens"

IDOR / Access Control Audit

You: "Login as admin and regular user. Find what the user shouldn't access."

Agent: container_setup (admin + user) → container_login (both)
       → navigate admin pages → compare_access
       → access_matrix
       → "User can reach GET /api/admin/users (200 instead of 403)"

WAF Bypass

You: "Test the search param for XSS. Bypass any WAF."

Agent: test_injection {types: ["xss"]} → all blocked
       → analyzes response: <script> stripped, events filtered
       → replay_request with <details/open/ontoggle=alert(1)> → REFLECTED
       → "Confirmed XSS via HTML5 ontoggle event bypass"

Offline HAR Analysis

You: "Import this HAR file and find injection candidates."

Agent: import_har → get_endpoints (87 found)
       → find_injection_points (23 candidates)
       → test_injection → "2 reflected XSS confirmed"

---

Tools Reference (39 tools)

<details> <summary><b>Browser Control (3)</b></summary>

Tool	Description
browser_launch	Launch Firefox with managed profile
browser_close	Close browser, auto-export HAR
browser_status	Protocol, containers, tab count, captured requests

</details>

<details> <summary><b>Containers (3)</b></summary>

Tool	Description
container_setup	Create 1-4 containers with roles and credentials
container_login	Login for a container (programmatic or manual)
container_list	List containers with auth status

</details>

<details> <summary><b>Navigation (4)</b></summary>

Tool	Description
navigate	Go to URL in a container tab
go_back / go_forward	Browser history navigation
wait_for	Wait for selector, URL, network idle, or JS condition

</details>

<details> <summary><b>Interaction (7)</b></summary>

Tool	Description
click	Click by CSS selector or text content
type_text	Type into input fields
select_option	Select dropdown value
submit_form	Submit a form
scroll	Scroll page or element
hover	Hover over element
press_key	Keyboard keys (Enter, Tab, Escape, etc.)

</details>

<details> <summary><b>Page Inspection (4)</b></summary>

Tool	Description
screenshot	Capture PNG screenshot
get_page_source	Full HTML source
get_dom_tree	Simplified DOM tree (LLM-friendly)
evaluate_js	Execute JavaScript and return result

</details>

<details> <summary><b>Traffic Capture (5)</b></summary>

Tool	Description
get_requests	List captured requests with filters (URL, method, status, MIME)
get_response	Full request/response details by ID
get_endpoints	Auto-discovered API endpoints with parameter templates
export_har	Save traffic as HAR 1.2 file
import_har	Load HAR from previous session

</details>

<details> <summary><b>Security Analysis (4)</b></summary>

Tool	Description
compare_access	Cross-container IDOR / broken authorization detection
access_matrix	Role x endpoint access grid
find_injection_points	Identify injectable params across 10 vuln types
replay_request	Replay with modified method, headers, body, URL

</details>

<details> <summary><b>Active Testing (3)</b></summary>

Tool	Description
test_injection	7 types, 60+ payloads, technique-labeled results
test_csrf	Replay without CSRF tokens
test_rate_limit	Rapid-fire requests, check for 429

</details>

<details> <summary><b>Auth Detection (3)</b></summary>

Tool	Description
detect_auth	Check session validity
detect_login_form	Find login form fields and CSRF token
auto_login	Auto-fill and submit login

</details>

<details> <summary><b>Discovery (2)</b></summary>

Tool	Description
crawl	BFS spider with form discovery and API extraction
get_sitemap	Return crawl results

</details>

<details> <summary><b>Reporting (1)</b></summary>

Tool	Description
generate_report	Security report (markdown/HTML) with findings and evidence

</details>

---

Library Usage

Use hackbrowser-mcp as a TypeScript library for custom tooling:

import {
  launchFirefox, closeFirefox,
  NetworkInterceptor, BrowserInteraction, Crawler,
  extractEndpoints, findInjectionPoints, testInjection,
  compareAccess, generateReport,
  buildHar, saveHar, loadHar,
} from "hackbrowser-mcp";

// Offline HAR analysis
const har = await loadHar("./capture.har");
const requests = harEntriesToRequests(har.log.entries);
const endpoints = extractEndpoints(requests);
const points = findInjectionPoints(requests);

console.log(`${endpoints.length} endpoints, ${points.length} injection candidates`);

---

Architecture

src/
├── browser/                 Firefox control
│   ├── bidi-client.ts       WebDriver BiDi protocol
│   ├── cdp-client.ts        CDP fallback
│   ├── launcher.ts          Binary detection + profile setup
│   ├── container-manager.ts Container isolation + extension WS
│   ├── interaction.ts       Click, type, scroll, hover
│   ├── crawler.ts           BFS spider
│   └── auth-detector.ts     Session detection
├── capture/                 Traffic
│   ├── network-interceptor.ts  Capture + auto-save (10K cap)
│   ├── har-builder.ts          HAR 1.2 builder
│   └── har-storage.ts          HAR I/O + merge
├── analysis/                Security engines
│   ├── active-tester.ts     60+ injection payloads
│   ├── injection-mapper.ts  Param → vuln type mapping
│   ├── endpoint-extractor.ts  API endpoint discovery
│   ├── container-differ.ts  Cross-role comparison
│   ├── access-matrix.ts     Role x endpoint matrix
│   └── report-generator.ts  Report formatting
├── protocol/
│   ├── tools.ts             39 tool definitions (Zod schemas)
│   └── mcp-server.ts        MCP stdio transport
└── types/                   TypeScript types

Design decisions:

• Firefox + BiDi first — Native Firefox protocol. Different rendering engine catches bugs Chrome-based tools miss. CDP available as fallback.
• Container isolation — Firefox Multi-Account Containers for true session separation. Not separate browser instances.
• Server-side fetch for testing — Active testing uses fetch() outside the browser to avoid polluting browser state.
• HAR 1.2 standard — Import/export for session continuity. Auto-save every 60s, resume on restart.
• Memory-bounded — 10K entry cap with FIFO eviction. 30s fetch timeout.
• Stealth by default — navigator.webdriver, UA, plugins, WebGL fingerprint all spoofed.

---

Limitations

• Firefox only (container isolation requires Firefox Multi-Account Containers)
• macOS / Linux (Windows not tested)
• One Firefox instance per port
• WebSocket frames not captured (only upgrade request)

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<p align="center"> <b>For authorized security testing only.</b><br> Always obtain proper permission before testing any application. </p>

<p align="center"> <a href="LICENSE">MIT License</a> • Built with Bun + TypeScript </p>