Bruteforce Series - Bruteforce attack SSH and FTP - 03

SSH Attack Overview

Objective: Understand and execute a brute force attack on an SSH service using Hydra.

Key Concepts and Skills

• Brute Force Attack: An attempt to crack passwords or keys through trial and error.

• Hydra: A powerful, multi-platform tool designed for password cracking by performing rapid dictionary or brute force attacks.

Step-by-Step Guide

a) Concept Explanation:

• SSH (Secure Shell): A cryptographic network protocol for operating network services securely over an unsecured network. Commonly used for remote server login and command execution.

• Hydra's Role: Utilizes username and password lists to systematically attempt logins, identifying valid credentials.

b) Preparing for the Attack:

1. Ensure Hydra is Installed: Confirm that Hydra is available on your system. It can typically be installed via package managers in Linux distributions.

   
    sudo apt-get install hydra
   

2. Gather Wordlists:

   • Username List (bill.txt): Contains potential usernames.

   • Password List (william.txt): Contains potential passwords.

These lists should be prepared based on known information about the target or using common username and password compilations.

3. Identify the Target: Obtain the IP address and SSH service port (typically 22) of the target system.

c) Executing the Attack:

hydra -L bill.txt -P william.txt -u -f ssh://TARGET_IP:22 -t 4

• L bill.txt specifies the username list.

• P william.txt specifies the password list.

• u instructs Hydra to use each username in the list only once.

• f tells Hydra to stop on the first valid password found for a username.

• ssh://TARGET_IP:22 defines the attack protocol and target.

• t 4 limits the number of parallel attempts to avoid connection drops.

d) Analyzing Results:

• Successful attempts will be clearly displayed by Hydra, showing valid username-password pairs.

• Login Using SSH: With valid credentials, you can log into the target system using:

  
    ssh USERNAME@TARGET_IP -p 22
  

FTP Brute Forcing Overview

Once access is gained to a system via SSH, further exploration and potential brute force attacks on other services like FTP can be considered.

Understanding FTP Service Vulnerability

a) Concept Explanation:

• FTP (File Transfer Protocol): Used for the transfer of files between a client and server on a network.

• Vulnerable to brute force attacks similar to SSH, especially when weak passwords are used.

b) Performing the Attack:

1. Identify the FTP Service: Confirm the presence and accessibility of an FTP service on the target system or network.

2. Utilize Hydra for FTP: Similar to the SSH attack, use Hydra with a targeted wordlist:

   
    hydra -l m.gates -P rockyou-10.txt <ftp://127.0.0.1>
   

   Adjust parameters as needed for the specific target and wordlist.

c) Post-Attack Actions:

• FTP Login: With valid credentials, you can login to the FTP service to explore or transfer files.

  
    ftp 127.0.0.1
  

• User Switching: If system access permits, switching to the compromised user account may provide additional privileges or access.

  
    su - USERNAME