RDP Brute Force Tools

TL;DR

Hydra is a powerful and flexible tool for brute-forcing RDP credentials. It’s command-line based, so it requires some technical knowledge but offers excellent control and speed. Ncrack is another good option with a slightly easier learning curve.

1. Understanding the Risks

Before you start, remember that attempting to brute force RDP without permission is illegal and unethical. This guide is for educational purposes only – specifically, for penetration testing on systems you own or have explicit permission to test. Brute-forcing can also lock out accounts and trigger security alerts.

2. Choosing a Tool: Hydra vs Ncrack

Both Hydra and Ncrack are popular choices:

• Hydra: More versatile, supports many protocols, faster in some cases, but steeper learning curve.
• Ncrack: Simpler syntax, easier to get started with, good for basic RDP brute-forcing.

We’ll focus on Hydra as it’s generally considered the more powerful option.

3. Installing Hydra

The installation process varies depending on your operating system:

• Kali Linux: Hydra is usually pre-installed. If not, use

  sudo apt update && sudo apt install hydra

  .

• Debian/Ubuntu: Use

  sudo apt update && sudo apt install hydra

  .

• Windows: Download a pre-compiled binary from a reputable source (e.g., GitHub) and add it to your PATH environment variable.

4. Basic Hydra Usage for RDP Brute-Forcing

The basic syntax is:

hydra -l  -P   rdp

• -l: Specifies the username to use.
• -P: Specifies the path to a password list file (text file with one password per line).
• : The IP address of the RDP server you are testing.
• rdp: Tells Hydra to use the RDP protocol.

Example:

hydra -l administrator -P /usr/share/wordlists/rockyou.txt 192.168.1.10 rdp

5. Optimizing Hydra for Speed

• -t: Number of threads (increase for faster brute-forcing, but be careful not to overload the server). Example:

  hydra -l administrator -P /usr/share/wordlists/rockyou.txt 192.168.1.10 rdp -t 16

  .

• -vV: Verbose mode (shows more output, useful for debugging).
• -f: Specifies a file containing usernames to try (one username per line). Example:

  hydra -l /usr/share/wordlists/usernames.txt -P /usr/share/wordlists/rockyou.txt 192.168.1.10 rdp

  .

• -o: Output file (saves successful credentials to a file). Example:

  hydra -l administrator -P /usr/share/wordlists/rockyou.txt 192.168.1.10 rdp -o results.txt

  .

6. Using Ncrack (Alternative)

Ncrack’s syntax is simpler:

ncrack -U  -P   --proto rdp --user-agent 'Mozilla/5.0'

• -U: Specifies the path to a username list file.
• -P: Specifies the path to a password list file.
• –proto rdp: Tells Ncrack to use the RDP protocol.
• –user-agent: Some servers require a user agent string.

Example:

ncrack -U /usr/share/wordlists/usernames.txt -P /usr/share/wordlists/rockyou.txt 192.168.1.10 --proto rdp --user-agent 'Mozilla/5.0'

7. Important Considerations

• Wordlist Quality: The effectiveness of brute-forcing depends heavily on the quality of your password list. Use common passwords, leaked databases (ethically sourced!), and variations of known passwords.
• Account Lockout Policies: Be aware of account lockout policies. Too many failed attempts can lock the account permanently. Reduce thread count if necessary.
• Firewalls & Intrusion Detection Systems: Firewalls and IDS may detect brute-force attacks. Consider using techniques to evade detection (e.g., slow down the attack, use multiple IP addresses).
• cyber security best practices: Always prioritize strong passwords and multi-factor authentication on RDP servers.