Exploit Notes

Add & Delete Users in Linux

Last modified: 2023-10-30

Linux

We can easily add/delete users in Linux using `useradd`, `userdel` commands.

Add Users

We can use useradd or adduser command to add users in Linux.

useradd <user>
adduser <user>

# -p: Specify password
useradd <user> -p <password>

# -u: Specify UID
# -g: Specify GID
useradd -u 1000 -g 1000 <user>

Set Password for User

# Set passwords. It's stored in "/etc/shadow"
passwd <user>

Delete Users

We can use userdel or deluser command to delete users in Linux.

userdel <user>
deluser <user>

# -r: Remove home directory and mail spool
userdel -r <user>

List Users in Linux

To list users exist in Linux, run the following commands.

cat /etc/passwd
cat /etc/shadow

Allow Users to Run Commands as Root Privilege

Add users to the “sudo” group.

usermod -a -G sudo <user>

# Check the permissions
su <user>
sudo -l