Secure Shell is one of the most common network protocols, typically used to manage remote machines through an encrypted connection. However, SSH is prone to password brute-forcing. Key-based authentication is much more secure, and private keys can even be encrypted for additional security. But even that isn't bulletproof since SSH private key passwords can be cracked using John the Ripper.
The standard way of connecting to a machine via SSH uses password-based authentication. This has the advantage of being easier to set up but suffers security-wise due to being prone to brute-forcing and password guessing.
how to crack ssh password
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In this tutorial, we learned about SSH key-based authentication and how to crack private key passwords. First, we created a new user on the target system and generated an SSH key pair. Next, we obtained the private key from the target and used ssh2john to extract the hash. Finally, we cracked the private key password and used it to connect to the target.
SSH, which stands for Secure Shell, is a network protocol that allows for encrypted communication over an insecure network. This was developed as an alternative to Telnet, which sends information in plaintext, which is clearly a problem, especially when passwords are involved.
The SSH cryptographic network protocol operates on a client-server model. That is, the client initiates a connection to the server, and communication is established after authentication takes place. SSH can use both password and private key authentication, the latter of which is considered more secure.
For the user and password files, I used a shortened list containing known credentials for the purpose of this demonstration. In a real attack, you would likely want to use one of the well-known wordlists or a custom one to fit your needs.
The next tool we will use is Hydra, a powerful login cracker which is very fast and supports a number of different protocols. To show the help and some basic usage options, simply type hydra in the terminal. (Note, if you were previously in the msf console, make sure you cd out of it before using Hydra.)
The last method of brute forcing SSH credentials we will try out today involves the use of the Nmap Scripting Engine. NSE contains a script which will attempt to brute-force all possible combinations of a username and password pair. To perform this attack, we can run a simple Nmap scan from a fresh terminal just like before, but with a few extra options tacked on:
Above, we can see it discovered three valid login credentials. This script is useful because it will iterate through all possible pairs of usernames and passwords, which will sometimes yield more results.
A better method is to implement a service like Fail2ban, DenyHosts, or iptables to block brute-force attempts at the host level. This, combined with using private key authentication instead of passwords, will put you out of the reach of most attackers. If password-based authentication is absolutely necessary, use strong passwords and follow best practices.
It is a tool that is widely used for cracking passwords. Even though originally it was built for Unix-based operating systems, nowadays it can be run on fifteen different platforms. Released in 1996 gradually it became a widely adopted tool that is still relevant nowadays.
It depends on the engagement rules. But once again, gaining access to a private SSH key is a critical security issue in itself. Reporting this finding to the client is enough. But if you do have the time for going deeper, you might want to use ssh2john for cracking the SSH key. Maybe you will log in to the system with this private key and will find there other vulnerabilities. Who knows.
Hello NullSec, Joker here with another Tutorial. This time I am gonna explain how to crack the password of a SSH which is one of several services that can be cracked with a Password Cracker like Hydra and Medusa. Of course there are other ways to obtain the password like Social Engineering, Exploit, etc. But one of the common ways is of course cracking the password itself.
If you wish to scan all the systems on the network simply put /24 at the end of the IP, which would look like this:nmap -sV -p 22 (ip)/24Once we determine that a SSH service is running on port 22, we can get cracking.
Oftentimes services will create users and will not disable SSH for those accounts. If you're lucky, the security will be lower for these service usernames. For example, if a server is running Postgresql, there should be a "postgres" username, it may allow you to log in, and it may even have the password "postgres".
However, if you don't know what username to use, and you know there is a MySQL serer listening, you can crack the MySQL server's password, and use the load_file() function in SQL to obtain the /etc/passwd or /etc/shadow file, and use those to obtain usernames and possibly password hashes. These may in turn lead to SSH usernames and passwords. It's a bit cumbersome, but who knows, you might get lucky and find some low-hanging fruit.
Once we load the MySQL exploit, we have to set the username and password to use. This requires us to know the username/password. You can try an empty password, or the word "password", or etc. On Metasploitable, no MySQL password is set by default:
Quick reality check: brute-forcing SSH logins is very slow (limited by how many SSH connections a victim's SSH server will accept), so if you have access to /etc/shadow, you might as well crack those passwords offline with John the Ripper.
This is extremely slow when compared to an offline password-cracking method like John the Ripper - if we have the /etc/shadow file, we should probably use that, instead of trying to brute-force SSH logins.
Hydra is a parallelized login cracker which supports numerous protocols to attack. It is a very fast, flexible, and new modules are easy to add in the attacks. This tool makes it possible for the researcher and security consultants to show how easy it would be to gain unauthorized access to a system remotely. We are using it the following way to crack the login.
Medusa is a speedy, parallel, and modular tool which allows login through brute force. Its goal is to support as many services that allow authentication possible. The key features of this tool are thread-based testing, Flexible user input, Modular design, and Multiple protocols supported. We are going to run this command to crack this log in.
Where [- h] use to assign the victim IP address, [- U] denotes the path for username list, [- P] denotes the path for the password list, [- M] to select the mode of attack. Now, the process of the dictionary attack will start. Thus, we will attain the username and password of our victim.
When we completed the details in the target tab, we need to switch into the password tab, where we need to fill up or browse the username and password list for the brute force attack. There are some extra options available in the tab like Try login as password, try empty password, and Try reversed login.
Patator is a multi-purpose brute-forcer, with a modular design and a flexible usage. Patator was written out of frustration from using Hydra, Medusa, Ncrack, Metasploit modules, and Nmap NSE scripts for password guessing attacks. I opted for a different approach to not create yet another brute-forcing tool and avoid repeating the same shortcomings. Patator is a multi-threaded tool written in Python, that strives to be more reliable and flexible than his fellow predecessors.
Ncrack is a network authentication tool, which helps the pen-tester to find out how the credentials that are protecting network access are vulnerable. This tool is a part of the Kali Linux arsenal and comes pre-installed with its package. It also has a unique feature to attack multiple targets at once, which is not seen very often in these tools. Run the following command to exploit port 22 via Ncrack.
Where [-U] helps us to assign to username list, [-P] helps us to assign the password list, and [-p] will help us to assign the service port number of the victim. We can see that we have successfully cracked the SSH credential.
In a similar fashion like the article about cracking a shadow file with John, we thought it would be a good idea to include how to crack SSH keys using John. It is another common concept you see in CTF events but also in real life. The process is relatively simple and the cracking method to chose is up to you. In this tutorial we are going to bruteforce the password using one of the common wordlists available in Kali.
The SSH Protocol uses the access credential SSH (Secure Shell). To put it another way, it is a cryptographic network protocol used to send encrypted data across a network. Without having to remember or type in your password for every system that needs to log in remotely from another system to a server, you can connect to one or more servers.
Hydra is an open-source tool that allows us to perform various kinds of brute force attacks using wordlists. It comes by default with all Pentesting Distros like Kali Linux. Hydra is a parallelized login cracker that can attack many different protocols. It is already installed in Kali Linux and is used to launch dictionary or brute-force attacks against username and password to several services, including MS-SQL, FTP, ssh, telnet, etc.
This article will focus on tools that allow remote service brute-forcing. These are typically Internet facing services that are accessible from anywhere in the world. Another type of password brute-force attack are against the password hash. Powerful tools such as Hashcat can crack encrypted password hashes on a local system.
I grabbed a list of 500 passwords from skullsecurity.org. Of course, you can find password lists with many thousands or even millions of passwords. You will need to choose what is most appropriate for your password testing as factors such as target type and rate of testing will be major factors. 2ff7e9595c
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