CVE-2020-0610 BlueGate Lab - Windows RD Gateway UDP/DTLS RCE

Nuclei PR: projectdiscovery/nuclei-templates#13076

A comprehensive reproducible laboratory environment for CVE-2020-0610 (BlueGate), a critical pre-authentication remote code execution vulnerability in Microsoft Windows Remote Desktop Gateway (RD Gateway). This lab enables security researchers to safely test and validate the vulnerability using minimal, non-destructive DTLS handshake techniques.

🎯 Vulnerability Overview

CVE-2020-0610 is a critical RCE vulnerability in Windows RD Gateway that allows unauthenticated attackers to execute arbitrary code by sending specially crafted UDP packets to port 3391. The vulnerability affects:

• Windows Server 2012 / 2012 R2
• Windows Server 2016
• Windows Server 2019
• Any system with RD Gateway role and UDP transport enabled

CVSS Score: 9.8 (Critical) Attack Vector: Network (UDP/3391) Authentication: None required Impact: Complete system compromise

🔬 Lab Scope & Safety

• Pre-authentication DTLS handshake on UDP 3391
• Single tiny fragment transmission (BlueGate "check" method)
• Non-destructive - no DoS flooding or system damage
• Isolated lab environment recommended
• Compatible with Nuclei security scanner templates

📋 Requirements

Infrastructure

• Hypervisor: Hyper-V / VMware Workstation / VirtualBox
• Target OS: Windows Server (2012/2012 R2/2016/2019) - unpatched
• Network: Isolated lab network
• Resources: 2GB RAM minimum, 40GB disk space

Tools

• PowerShell (Admin privileges required)
• Nuclei Scanner v3.4.10+
• Network connectivity testing tools (optional)

🚀 Quick Setup Guide

1. Install RD Gateway Role

# Via Server Manager GUI
Server Manager → Add Roles and Features → Remote Desktop Services → RD Gateway

2. Enable UDP Transport

# Via RD Gateway Manager
RD Gateway Manager → <ServerName> → Properties → Transport Settings
→ Check "Allow users to connect by using UDP" → OK

3. Configure Firewall (UDP/3391)

# Run as Administrator
powershell -ExecutionPolicy Bypass -File .\scripts\add-udp-3391-firewall.ps1

4. System Validation

# Verify RD Gateway and firewall configuration
powershell -ExecutionPolicy Bypass -File .\scripts\sanity-check.ps1

5. Vulnerability Testing

# Using Nuclei scanner
nuclei -t network/cves/2020/CVE-2020-0610.yaml \
       -u <target_host> \
       -var rdg_port=3391 \
       -var dtls_timeout=6 \
       -debug

🔍 Expected Results

Vulnerable System

DEBUG_HEX:
NUCLEI_RESULT:VULNERABLE

Patched System

DEBUG_HEX: 160303...ffff0080
NUCLEI_RESULT:NOT_VULNERABLE

The key indicator is the presence of the ffff0080 trailer (little-endian representation of 0x8000ffff) in patched systems.

📁 Repository Structure

lab-rdg-bluegate/
├── README.md                           # This comprehensive guide
├── scripts/
│   ├── add-udp-3391-firewall.ps1     # Firewall configuration
│   └── sanity-check.ps1               # System validation
└── samples/
    ├── nuclei-debug-vulnerable.txt    # Example vulnerable output
    └── nuclei-debug-patched.txt       # Example patched output

🛡️ Security Considerations

• Isolation: Always run in isolated lab environments
• Snapshots: Use VM snapshots for easy rollback
• Network Segmentation: Prevent lab network access to production
• Responsible Disclosure: Use only for authorized testing
• Patch Management: Apply security updates after testing

🔗 Related Resources

Official Documentation

• Microsoft Security Advisory
• NVD Entry - CVE-2020-0610

Research & Analysis

• Kryptos Logic - RDP to RCE Analysis
• BlueGate PoC Repository
• VulnCheck Database Entry

Security Tools

• Nuclei Scanner
• ProjectDiscovery Templates

🤝 Contributing

This lab was created to support the security research community. Contributions are welcome:

• Improve setup scripts
• Add additional test cases
• Enhance documentation
• Report issues or bugs

⚖️ Legal Disclaimer

This laboratory environment is provided for educational and authorized security testing purposes only. Users are responsible for:

• Obtaining proper authorization before testing
• Complying with applicable laws and regulations
• Using the lab ethically and responsibly
• Not targeting systems without explicit permission

🏷️ Keywords

CVE-2020-0610 BlueGate RD Gateway Windows Server Remote Code Execution UDP DTLS Nuclei Security Research Vulnerability Lab Penetration Testing Red Team Blue Team Cybersecurity