Overview

Smugglex is a powerful HTTP Request Smuggling testing tool written in Rust, designed for security testing and penetration testing to detect various types of HTTP request smuggling vulnerabilities.

What is HTTP Request Smuggling?

HTTP Request Smuggling is a critical web security vulnerability that exploits discrepancies in how front-end and back-end servers parse HTTP requests. When multiple systems in a chain (like a proxy and a web server) disagree on where one request ends and another begins, attackers can "smuggle" malicious requests through security controls.

How It Works

HTTP Request Smuggling occurs when there's a disagreement between front-end and back-end servers about request boundaries. This typically involves two key HTTP headers:

• Content-Length: Specifies the length of the message body in bytes
• Transfer-Encoding: Specifies the form of encoding used to transfer the message body

When these headers conflict or are obfuscated, different servers may interpret them differently, leading to request boundary confusion.

Security Impact

Request smuggling vulnerabilities can lead to:

• Bypassing Security Controls: Circumvent WAFs, IDS/IPS, and other security measures
• Cache Poisoning: Poison web caches to serve malicious content to other users
• Session Hijacking: Steal other users' session tokens and cookies
• Access Control Bypass: Access unauthorized resources or admin panels
• Request Hijacking: Intercept and modify other users' requests
• Credential Theft: Capture sensitive data from subsequent requests

Why Smugglex?

Smugglex provides comprehensive coverage of HTTP request smuggling attack vectors with:

Multiple Attack Types

• CL.TE (Content-Length vs Transfer-Encoding): Front-end uses Content-Length, back-end uses Transfer-Encoding
• TE.CL (Transfer-Encoding vs Content-Length): Front-end uses Transfer-Encoding, back-end uses Content-Length
• TE.TE (Transfer-Encoding Obfuscation): Both use Transfer-Encoding but one can be fooled with obfuscation (60+ variations)
• H2C (HTTP/2 Cleartext Smuggling): Exploits HTTP/1.1 to HTTP/2 upgrade mechanisms (20+ payloads)
• H2 (HTTP/2 Protocol Smuggling): Exploits HTTP/2 protocol-level features (25+ attack vectors)

Advanced Detection

• Timing-Based Detection: Uses sophisticated timing analysis to detect desynchronization
• Extended Mutation Testing: 60+ variations of Transfer-Encoding header obfuscations
• HTTP/2 Protocol Support: Full H2C and H2 protocol-level desync detection
• Connection Timeout Detection: Identifies vulnerabilities through connection behavior analysis

Flexible Testing Options

• Custom Headers: Add custom headers to test specific scenarios
• Cookie Support: Automatically fetch and include cookies in tests
• Virtual Host Testing: Test different virtual hosts on the same IP
• Method Customization: Use different HTTP methods (GET, POST, etc.)
• Timeout Configuration: Adjust timeouts for different network conditions
• Selective Scanning: Choose specific attack types to test

Integration & Automation

• Pipeline Support: Read URLs from stdin for integration with other tools
• JSON Output: Export results in JSON format for further analysis
• Payload Export: Save vulnerable payloads for manual verification
• Exit First Mode: Stop after finding the first vulnerability for quick checks
• Progress Tracking: Real-time progress bars and status updates

Performance

• Built with Rust: High-performance, memory-safe implementation
• Async Operations: Efficient concurrent testing with tokio
• Fast Scanning: Optimized for quick vulnerability detection
• Resource Efficient: Low memory footprint and CPU usage

Key Features

🎯 Comprehensive Attack Coverage

Smugglex supports all major HTTP request smuggling attack types with extensive payload variations. The tool includes research-based obfuscation techniques from security researchers and bug bounty hunters.

⚡ High Performance

Written in Rust and leveraging async operations, smugglex provides fast and efficient scanning without compromising accuracy. The tool can test hundreds of payload variations quickly.

🔍 Accurate Detection

Uses timing-based detection algorithms to minimize false positives. The tool analyzes response timing patterns to reliably identify desynchronization vulnerabilities.

🛠️ Flexible Configuration

Customize every aspect of testing including HTTP methods, headers, cookies, timeouts, and virtual hosts. The tool adapts to your specific testing requirements.

📊 Detailed Reporting

Get comprehensive scan results with vulnerability details, payload indices, timing information, and response analysis. Export results in JSON format for documentation and further analysis.

🔗 Tool Integration

Seamlessly integrate with other security testing tools through stdin pipeline support. Smugglex works great with subdomain enumeration tools, web crawlers, and security scanning pipelines.

Use Cases

Security Testing

• Penetration Testing: Identify request smuggling vulnerabilities during authorized penetration tests
• Bug Bounty Hunting: Discover high-impact vulnerabilities in bug bounty programs
• Security Audits: Assess web application security posture for request smuggling risks

Research & Education

• Security Research: Explore HTTP request smuggling attack techniques
• Learning Tool: Understand how request smuggling vulnerabilities work
• Training: Practice identifying and exploiting request smuggling in lab environments

DevSecOps

• CI/CD Integration: Integrate into security testing pipelines
• Pre-deployment Testing: Test applications before production deployment
• Regression Testing: Verify fixes for request smuggling vulnerabilities

Ethical Use

⚠️ Important: Smugglex is a powerful security testing tool that should only be used:

• On systems you own or have explicit written permission to test
• In authorized penetration testing engagements with proper contracts
• For educational purposes in controlled lab environments
• In responsible security research with proper disclosure

Unauthorized testing of web applications may be illegal in your jurisdiction and could result in criminal charges. Always obtain proper authorization before testing any system.

Next Steps

Ready to get started? Head over to the Installation guide to install smugglex and begin testing.