Skip to main content

How to List all the "Normal Users" in Linux

I have started to take some challenges on the website called Try Hack Me. I think it's a great way to be more aware of the potential security flaws of my own applications. Plus let's be honest, it's very fun!

Anyway, yesterday I learned how to list the users of a Linux system and understand what kind of account I was looking at. It's pretty cool.

I didn't know, but each user has an ID automatically allocated when they are created. IDs allocated to "normal users" have a min and a max. Those bound can be changed, but I think the default is from 1,000 to 60,000. By "normal users", I mean users created by an admin with the purpose of providing a working access to the machine.

To make sure of those two numbers, you can run:

grep -E '^UID_MIN|^UID_MAX' /etc/login.defs 

 From there, you just have to list the users by using this command (replace UID_MIN/MAX by the values you just found out).

getent passwd {UID_MIN..UID_MAX}

Tadddaaaa! You just got a list of all the normal users on a machine. I found this commands and more on the website Linuxize, on this page. It was very well explained, check it out if you need more!

Comments

Post a Comment

Popular posts from this blog

How to generate a self-signed certificate with Openssl (using git windows bash)

I recently needed to generate a self-signed certificate to test a website locally. I wasn't familiar with the process, and I wanted to share here what I learned. First, we need a private key. A private key is a long series of characters that must be kept secret. In my context, it will be used to encrypt messages before the client and the server, in a way secure enough to prevent anybody to spy on them. Once the private key is created, we need to generate another file that will be the "signature" of our certificate. Among other data, this file will contains some information specific to the server's context: country, organization's name, email address of the organization's technical contact, etc. Once this signature is established, there are two paths: - Path A: If we want our server to be publicly accessible, every browser in the world must able to trust the certificate. In order for that to happen, we need to send our signature file to one of the official SSL ...
Post a Comment
Read more

How to Compile a GTK4 program on Windows (using MSYS)

  I wanted to create a GUI program using C and GTK. I am using a windows operating system, so I had followed the instructions from the GTK Windows installation page . However, when trying to compile my program using: gcc main.c -o main.exe `pkg-config --cflags --libs gtk4` I had the following errors: gcc.exe: error: pkg-config: No such file or directory gcc.exe: error: gtk4`: No such file or directory gcc.exe: error: unrecognized command-line option '--cflags' gcc.exe: error: unrecognized command-line option '--libs' I noticed that the command  pkg-config --cflags --libs gtk4 was actually returning a list of required includes. It seemed that the gcc command simply was not able to recognize them. To solve the problem, I then created a Makefile, in which a variable called GTK_4_INCLUDES contains the list of includes.  The compilation command becomes:   gcc main.c -o main.exe $(GTK_4_INCLUDES) To compile the program in the console, I just had to type mingw32-make , a...
Post a Comment
Read more

Fixing x-invalid-end-tag lint error on Vuejs

  My situation is: Coding with vue in a Vue file. Using the Vetur plugin in VS code It then generates an error of type x-invalid-end-tag in a quite random fashion. To solve it, I have found one simple trick in this github issue: // .eslintrc.js module.exports = {  //... rules:  { 'vue/no-parsing-error': [2, { 'x-invalid-end-tag': false }]  }  }
Post a Comment
Read more