Have you heard the story of Jack the Ripper? Well, you'd better know it because it is the one that gives the name to the program we will analyze next. We are talking about John the Ripper, a tool that computer scientists will use for years. Although today we will talk about how to use it for system administration, it is widely used for hacking or cracking all kinds of content.

The truth is that security specialists can ideally use John the Ripper, considering that if we take it as a counterpart of its hacking functions, we can use it to our advantage to protect ourselves from them. If you want to ensure that all the elements on your computer are safe, you can rest assured that this platform will help you solve these issues quickly.

You have to bear in mind, however, that when we use this program for such purposes, we are using a reactive platform, which, as we said before, we use for a purpose that is often different from the usual one. Many consider that proactive tools, i.e., specially developed to defend against attacks, are more secure. But that is up to each user to decide.

With this cryptographic application, we can recover passwords from the different data around the system. Although they often seem insignificant, they can end up causing damage. In its most noble use, this is an ideal option if you have doubts about the security of a password because if this program can unlock it, it is weak.

One of the main differences between John the Ripper and other similar programs is that it uses brute force to guess different passwords and has many other methods to obtain information. One of the modes we have found most interesting is the one that bets on looking for the most insecure passwords. Our system generally has to mark them one by one and modify them.

To give you an idea of how John the Ripper works, we will take the example of the Single Mode since it is the simplest of all. This program will take information such as the system user name, the actual name of the computer owner, and other loose data, generating all kinds of combinations with numbers and letters, and trying to crack your passwords. If any of them pops up, we recommend you change them as soon as possible.

Then, as for its interface, we can say that in what is essential, which is the location of the functions and how intuitive it is, it more than fulfills. However, it is true in the same way that we find that it could be more attractive to the eye. This is not a reason to dismiss this tool, far from it, but a simple superficial observation about what it offers to the eyes.

How to use John the Ripper? First, you will need to get a copy of the Security Account Manager file, also known as SAM, on your Windows computer, where the encrypted usernames and passwords are located. Once you have it at hand and you have installed this platform, you will need to go to the operating system command console and add the following:

john keyfile

You will see the methods we mentioned before, from Single to others. Conveniently, you start using this one, and as you get to know the program better, try the others, but we can tell you that when you finish with them, you will have to add another command to visualize the results obtained:

john --show keyfiles

In general terms, we can say this is a valuable program, which we would probably not recommend as the only precaution in case you consider your passwords somewhat insecure. Still, it could give you a hand to detect them. The truth is that John the Ripper is entirely stable and has not given us any particular performance problem worth mentioning.

Suppose we add that it is an open-source program, which ensures that we can download it for free anytime we want. In that case, we do not doubt that we are in the presence of one of the must-haves for security obsessives who, however, do not want to spend money while analyzing the strength of their passwords.

Finally, and although we think it should not be repeated, you should remember that this tool has been designed so that system administrators can check the vulnerability of the network passwords they have on their computers so that they can detect weak ones before someone else does. In no way should you take advantage of this program to crack the passwords of a network that is not yours.