**Note: The content in this article is only for educational purposes and understanding of cybersecurity concepts. It should enable people and organizations to have a better grip on threats and know how to protect themselves against them. Please use this information responsibly.**
A brute force attack tries to crack passwords by attempting every possible combination. This straightforward hacking method packs a punch.
How It Works
- Uses programs to create countless guesses
- Tests dictionary words, popular passwords, or every character combo
Types
- Simple: Every combination
- Dictionary: Everyday words
- Hybrid: Words plus symbols
Targets
- Passwords, encryption keys, hidden web pages, API keys
Effectiveness
- Works better on short basic passwords
- Takes ages for complex ones
Defences
- Tough passwords
- Account freezes
- Two-step verification
- CAPTCHA
- Capped login tries
Legal Issues
- Security experts use it to test defences
- Using without permission is against the law
Brute-Force Attack with Hashcat
Considered to be one of the best password recovery tools in the market, Hashcat is widely used in both offensive and defensive cybersecurity strategies. Speed and versatility make Hashcat an invaluable tool not only for penetration testers and security researchers but also for bad actors since it is commonly used to brute-force password hashes.
How does Hashcat work? In general, it tries to get all the permutations of passwords and compares them with our target hashed password. Then, we repeat this process until a match is found or all possibilities are exhausted. The tool is fast because it uses GPUs and can test millions or even billions of combinations each second, depending upon the hardware.
While Hashcat is a reputable and highly-trusted professional-grade tool for legitimate security testers & password recovery, it’s so powerful that it’s very use makes it quite appealing to malicious hackers. That is why it has to be mentioned that Hashcat should only ever be used ethically and legally, with permission.
Step 1: Identify the Hash Type
You need to know the hash type you are trying to crack. Hashcat supports a wide range of hash types, and each has a specific mode identifier. For example, MD5 is 0, SHA-1 is 100, etc.
Step 2: Prepare Your Hash File
Create a file containing the hash you want to crack. Let’s assume the file is named hashes.txt and contains a single hash.
Step 3: Choose a Charset and Mask
Brute-force attacks require a charset and a mask to define the range of characters and the length of the password.
- A mask defines the pattern of the password:
- ?l – Lowercase letters
- ?u – Uppercase letters
- ?d – Digits
- ?s – Special characters
- ?a – All printable ASCII characters
For example, to attempt all combinations of lowercase letters with a length of 4:
- Mask: ?l?l?l?l
Step 4: Run Hashcat
Run Hashcat with the appropriate options. Here’s a basic example:
If you do not know the length of the password, use increment and set minimum range and maximum range and perform brute-force.
Incremental Mode: Start with shorter lengths and gradually increase.
Using Medusa for Brute-Force Attacks:
Medusa is a powerful and versatile open-source tool designed to conduct online brute-force attacks against various network services. As a parallel, modular login brute-forcer, Medusa has gained popularity among both cybersecurity professionals and ethical hackers for its efficiency and flexibility in testing system security.
Originally developed as an alternative to older tools like Hydra, Medusa offers improved performance and a more user-friendly approach to conducting brute-force attacks. It supports a wide range of protocols including, but not limited to, HTTP, FTP, SSH, SMTP, and Telnet, making it a comprehensive tool for security testing across different network services.
Step 1: Identify the Target
Determine the target service and IP address or hostname you want to brute-force. You will also need a list of usernames and passwords.
Step 2: Prepare Username and Password Lists
Create or obtain files containing possible usernames and passwords. For example:
- user.txt
- paas.txt
Step 3: Run Medusa
Run Medusa with the appropriate options to perform the brute-force attack. Here are some examples for different services:
Example 1: Brute-Forcing SSH
To brute-force an SSH service on a target IP 192.16840.129:
FTP Brute Force Attack on a Specific Port:
Example 2: Brute-Forcing FTP
To brute-force an FTP service on a target IP 192.168.40.129:
Brute force attacks those using tools like Hashcat and Medusa, are still major threats in the world of cybersecurity. These tools have different methods, but they both aim to crack passwords and get into systems without permission.
Hashcat is good at breaking passwords. It uses the power of GPUs to check huge numbers of password combinations against stolen password hashes. It’s so good at handling different types of hashes that both cybersecurity experts and hackers like to use it.
Medusa, on the other hand, focuses on online brute force attacks against network services. It’s particularly effective against protocols like HTTP, FTP, and SSH, allowing attackers to attempt multiple login combinations remotely.
Both tools highlight the ongoing importance of strong password policies and additional security measures like multi-factor authentication. They serve as reminders that relying solely on passwords, especially weak ones, is insufficient in today’s threat landscape.
For defenders, understanding these tools is crucial for strengthening defences and conducting ethical penetration testing. For organizations, regular security audits, employee training, and implementing robust authentication methods are essential to mitigate the risks posed by such brute force attacks.
Ultimately, the existence and effectiveness of tools like Hashcat and Medusa underscore the need for continuous advancement in cybersecurity practices to stay ahead of potential threats.
