How to edit the /etc/passwd file

Show Posts. Registered User. Join Date: Aug I tried to open the file in vi editor and changed the comment, but next day it's getting reverted back again. Join Date: Sep That sort of behaviour normally happens when you have a master file somewhere on you network that synchronizes all slave boxes overwrites but also if someone asked a restoration Join Date: Mar I agree with vbe.

Sounds like a slave machine. Some general advice not relevant to this post: You should avoid using "vi" directly on the password file becase it does not maintain the password file lock or the password cache. Ensure that the user is not logged in and use "usermod" instead. As a last resort use "vipw" a special version if "vi" if you really must edit the password file directly. Always copy the password file before any manual edits. The root user has read and write permissions, and the "shadow" group, which contains users needed for authentication, has read permissions.

This is mainly used for services and is intended behavior. By default, this command changes the current user's password and does not require special permissions. If you would like to change another user's password, you will need administrative privileges. The following syntax can be used:. You will be prompted for your password for the "sudo" command, and then you will be told to enter and confirm the new password you would like to use.

The easiest method is probably with the " adduser " command, which we will cover here. On Ubuntu systems, this is linked to a perl script that handles appropriate user creation. You can see that this takes great advantage of the comments field.

The other fields are filled in as expected. It is important to test your ability to log in after making any changes. It is also essential to keep the permissions on the authentication files the same to maintain functionality and security.

How Do You Change Passwords? Where would you like to share this to? Twitter Reddit Hacker News Facebook. Share link Tutorial share link. Sign Up. NOTE: Each field is separated by colon. Here gid denotes it is a non-system user. So here you can clearly match the following information from below given image. Now, set a password for user2 with passwd command and enter the password.

In this way, we can create our own user for privilege escalation. Sometimes it is not possible to execute passwd command to set the password of a user; in that case, we can use OpenSSL command which will generate an encrypted password with salt. Now switch user and access the terminal through user3 and confirm the root access. It will generate a hash for your password string, repeat above step or change the password of other existed users.

If you will compare entry of user1 then you can notice the difference. We have replaced: X: from our hash value. Now switch user and access the terminal through user1 and confirm the root access. To view it, we can use any regular file viewer command such as cat, less, more, etc.

There is one entry per line. Identifying users uniquely is essential and necessary at the time of login. It displays the username of the current user when this command is invoked.