D-Link DIR600 Remote Code Execution Exploit Chain

Overview

This repository contains a complete exploit chain targeting D-Link DIR600 routers, designed to achieve remote code execution and establish persistent network access through a single HTTP link. The exploit leverages multiple vulnerabilities to weaponize home routers and create covert tunnels into internal networks.

The Challenge

The initial objective was to gain control over internal networks by exploiting vulnerabilities in home routers. Since these devices are typically not exposed to the internet, the critical requirement was finding vulnerabilities exploitable via CSRF (Cross-Site Request Forgery) attacks through malicious web links.

Initial Research Constraints

The original research timeline was extremely tight - only one week without physical access to devices for debugging and analysis. After three days with minimal progress, I pivoted the research approach entirely.

However, those initial days provided crucial insights into the vulnerability requirements needed to compromise routers and establish internal network positioning.

Vulnerability Requirements

For a successful exploit chain, the target router needed to satisfy these conditions:

1. CSRF Vulnerability: No CSRF token validation
2. Authentication Issues: Default credentials or authentication bypass
3. CORS Misconfiguration: Accept HTTP requests from any origin (if using default credentials)
4. Remote Code Execution: A vector for achieving command execution

Research Pivot

Instead of discovering new vulnerabilities in untested devices, I shifted focus to identifying existing devices that already met all vulnerability criteria. The goal became creating a full exploit chain that combined these weaknesses for complete device compromise.

Technical Challenges

Binary Upload via HTTP

The primary challenge was the router's lack of built-in tools for establishing reverse shells. This required:

• Generating a MIPS LSB32 binary (matching the router's processor architecture)
• Uploading the binary in chunks via HTTP requests
• Reconstructing the binary using echo commands
• Bypassing multiple HTTP request processing restrictions

Special thanks to Q3rv0 for collaborative work on HTTP byte processing bypasses.

Post-Exploitation Weaponization

After gaining initial access, the objective expanded to weaponizing the router for persistent access:

• Installing a SOCKS proxy server for traffic tunneling
• Cross-compiling tools for MIPS LSB architecture
• Establishing external connectivity through port exposure

Network Exposure Challenge

Since routers typically don't expose ports to the internet by default, establishing external connectivity required:

• Analyzing router behavior and port forwarding mechanisms
• Understanding internal DMZ implementation
• Reverse engineering iptables rule creation for DMZ configurations

The Complete Exploit

Capabilities

The final automated exploit achieves the following through a single HTTP link:

• Complete Router Compromise: Exploits the full vulnerability chain on D-Link DIR600 devices
• Security Bypass: Disables router protections and creates internet exposure via DMZ
• Persistent Access: Installs a SOCKS proxy server for traffic tunneling from external networks
• Remote Administration: Enables telnet access with credentials root:w00tw00t!
• Stealth Operation: Maintains factory configuration appearance - all traces disappear on device reboot

Target Impact

Current Shodan/ZoomEye data shows approximately 7,800 vulnerable devices exposed to the internet:

Important Note: These figures only represent internet-exposed devices. The exploit can target internal routers (typically at 192.168.0.1 or other local IPs) via CSRF attacks through malicious web links, significantly expanding the potential victim pool beyond publicly visible devices.

Repository Structure

├── DMZ/                          # DMZ configuration scripts
├── curl_mipsle/                  # MIPS cross-compiled curl binary
├── exploit_dir600.html           # Main exploit payload
├── firmware/                     # Extracted firmware analysis
├── microsocks/                   # SOCKS proxy server for MIPS
├── reverse_shells/               # Reverse shell payloads
└── shellcode utilities/          # Shellcode conversion tools

Usage

⚠️ Warning: This tool is for educational and authorized testing purposes only. Unauthorized access to computer systems is illegal.

1. Host the exploit HTML file on a web server
2. Social engineer the target to visit the malicious link
3. The exploit automatically executes the full chain
4. Access the compromised router via the installed SOCKS proxy

Technical Details

• Target: D-Link DIR600 routers
• Architecture: MIPS LSB32
• Attack Vector: CSRF via malicious web links
• Persistence: Temporary (removed on reboot)
• Network Access: SOCKS proxy tunneling

Disclosure

This research demonstrates the critical security risks present in legacy home networking equipment. The vulnerabilities exploited are well-documented, and this work serves to highlight the importance of:

• Regular firmware updates
• Default credential changes
• Network segmentation
• CSRF protection implementation

Contributors

• Primary Research: Alejandro Parodi (hdbreaker)
• HTTP Bypass Techniques: Q3rv0

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This research was conducted for educational purposes and responsible disclosure practices.