xssmaze

XSSMaze is an intentionally vulnerable web application for measuring and improving XSS detection in security testing tools. It covers a wide range of XSS contexts: basic reflection, DOM, header, path, POST, redirect, decode, hidden input, in-JS, in-attribute, in-frame, event handler, CSP bypass, SVG, CSS injection, template injection, WebSocket, JSON, advanced techniques, polyglot, browser-state, opener, storage-event, stream, channel, service-worker, history-state, reparse, referrer, jQuery DOM sinks, dynamic code/module execution sinks, client-state (web storage/cookie/history) sinks, and async fetch/XHR API DOM sinks.

Installation

From Source

shards install
shards build
./bin/xssmaze

From Docker

docker pull ghcr.io/hahwul/xssmaze:main
docker run -p 3000:3000 ghcr.io/hahwul/xssmaze:main

Usage

./bin/xssmaze

Options:
  -b HOST, --bind HOST             Host to bind (defaults to 127.0.0.1; pass 0.0.0.0 to expose on the network)
  -p PORT, --port PORT             Port to listen for connections (defaults to 3000)
  -s, --ssl                        Enables SSL
  --ssl-key-file FILE              SSL key file
  --ssl-cert-file FILE             SSL certificate file
  -h, --help                       Shows this help

Dynamic Security Headers (Query Params)

For calibrating scanners against different defensive configurations, XSSMaze can override common security headers per-request via URL query parameters (works on any endpoint).

• set_csp: sets Content-Security-Policy (URL-encode spaces/quotes)
• set_xcto: sets X-Content-Type-Options (e.g. nosniff)
• set_xfo: sets X-Frame-Options (e.g. DENY)

Examples:

curl -i "http://localhost:3000/basic/level1/?query=a&set_xcto=nosniff"
curl -i "http://localhost:3000/basic/level1/?query=a&set_xfo=deny"
curl -i "http://localhost:3000/basic/level1/?query=a&set_csp=default-src%20%27self%27"

Endpoint Map

curl http://localhost:3000/map/text         # newline-separated URLs
curl http://localhost:3000/map/json         # full metadata (also: ?type=dom or ?q=csp)
curl http://localhost:3000/map/markdown     # markdown table
curl http://localhost:3000/map/categories   # categories with counts
curl http://localhost:3000/map/openapi      # OpenAPI 3.0 catalog
curl http://localhost:3000/sitemap.xml      # sitemap of all maze paths
curl http://localhost:3000/health           # liveness probe
curl http://localhost:3000/version          # version + counts
curl -L http://localhost:3000/random        # 302 to a random maze

The index page (/) provides a client-side filter, per-category counts, and links to all of the maps above. Map endpoints serve a payload that is built once at startup, cached, and gzip pre-compressed (Accept-Encoding: gzip cuts the index payload by ~85%), so they're safe to poll from tooling.

XS-Leaks (Cross-Site Leaks)

XS-Leaks are cross-origin side-channels that let an attacker infer state-dependent data without directly reading the response body. XSSMaze includes xsleak-* levels that intentionally vary response size, subresource composition, load/error behavior, timing, and redirect chains based on a "secret" state.

The state can be controlled either by:

• q=admin (simple stateless demos for scanners), or
• the xsleak_role=admin cookie (set via GET /xsleak/login?as=admin).

Levels

• GET /xsleak/search?q=admin (xsleak-level1): body-size oracle (admin returns more HTML/results)
• GET /xsleak/frame?q=admin (xsleak-level2): frame-count oracle (admin includes more iframes)
• GET /xsleak/avatar.gif?q=admin (xsleak-level3): load/error oracle (admin returns an image, guest is 404)
• GET /xsleak/timing?q=admin (xsleak-level4): timing oracle (guest path sleeps longer)
• GET /xsleak/redirect?q=admin (xsleak-level5): redirect-chain oracle (admin has more hops)

Measuring side-channels

To validate dynamically, host an "attacker" page on a different origin and probe the victim endpoints using load/error handlers and timing:

<script>
  // Load/error oracle (200 vs 404)
  const img = new Image();
  img.onload = () => console.log("loaded");
  img.onerror = () => console.log("error");
  img.src = "http://127.0.0.1:3000/xsleak/avatar.gif?q=admin";

  // Timing oracle (measure duration)
  const t0 = performance.now();
  fetch("http://127.0.0.1:3000/xsleak/timing?q=admin", { mode: "no-cors" })
    .finally(() => console.log("ms:", performance.now() - t0));

  // Frame-count oracle (browser-dependent)
  const f = document.createElement("iframe");
  f.src = "http://127.0.0.1:3000/xsleak/frame?q=admin";
  f.onload = () => console.log("subframes:", f.contentWindow.length);
  document.body.appendChild(f);
</script>

You can also spot differences via CLI:

curl -i "http://localhost:3000/xsleak/avatar.gif?q=guest"   # 404
curl -i "http://localhost:3000/xsleak/avatar.gif?q=admin"   # 200 image/gif
curl -s "http://localhost:3000/xsleak/frame?q=guest" | wc -c
curl -s "http://localhost:3000/xsleak/frame?q=admin" | wc -c
curl -sL -o /dev/null -w "%{time_total}\n" "http://localhost:3000/xsleak/timing?q=guest"
curl -sL -o /dev/null -w "%{time_total}\n" "http://localhost:3000/xsleak/timing?q=admin"

Benchmarking Scanner Tools

XSSMaze includes an automated benchmark tool to measure how well XSS scanners perform against the lab's diverse vulnerability scenarios. The tool retrieves all endpoints from /map/json, runs scanner tools against them, and generates a detection scorecard.

Requirements

• Python 3.x
• requests library (pip install requests)
• Scanner tools (e.g., Nuclei)

Quick Start

# Start XSSMaze (in one terminal)
./bin/xssmaze -b 0.0.0.0

# Run benchmark (in another terminal)
cd scripts
./benchmark.sh http://localhost:3000

Usage Examples

# Basic benchmark with console output
python3 benchmark.py http://localhost:3000

# Verbose mode (shows detailed progress)
python3 benchmark.py http://localhost:3000 -v

# Generate markdown report
python3 benchmark.py http://localhost:3000 -o report.md

# Run specific scanner only
python3 benchmark.py http://localhost:3000 --scanner nuclei

# Use a custom scanner command
python3 benchmark.py http://localhost:3000 \
  --custom-scanner "myxss {URL}" \
  --custom-scanner-name "MyXSSScanner"

Output Format

The benchmark tool provides:

• Console Scorecard: Summary table showing detection rates for each scanner
• Detailed Statistics:
  • Total registered endpoints
  • Endpoints successfully detected (True Positives)
  • Endpoints missed (False Negatives)
  • Overall detection rate percentage
  • Breakdown of missed detections by category
• Markdown Report (optional): Exportable report with full benchmark results

Example output:

======================================================================
XSSMaze Scanner Benchmark Results
======================================================================

Target: http://localhost:3000
Total Registered Endpoints: 450
Categories: 45

Scanner              Detected     Missed       Rate         Time (s)
----------------------------------------------------------------------
Nuclei               234          216          52.0%        125.3s

--- Nuclei Detailed Results ---
✓ True Positives: 234/450
✗ False Negatives (Missed): 216/450

Missed by category:
  advanced: 6/6 missed
  csp-bypass: 5/5 missed
  template-injection: 6/6 missed

Supported Scanners

The benchmark tool currently supports:

• Nuclei: Uses XSS-related templates from the Nuclei template library
• Custom Scanners: Any tool that can accept a URL and output results

Adding New Scanners

To add support for a new scanner:

1. Use the --custom-scanner option with command template
2. Or extend benchmark.py with a new scanner method

Example for adding a scanner permanently:

def run_my_scanner(self) -> ScannerResult:
    # Implementation here
    pass