Linux – Change Passwords for All Users on Linux Server

command-line-interfacelinuxpasswordscriptingSecurity

I've got 10 Linux servers that I need to lock down, by resetting the passwords for every single user all at once. The story behind this is long, but the general idea is that I need it to happen very quickly at a specific time. I'm going to use a single, tough password for all the user accounts (just initially), so this doesn't need to read from a password file or anything like that.

So what I need is the best way to script this out so I can reset all the passwords at once. I can extract a list of the user accounts with the cat /etc/passwd | cut -f1 -d: command, but that ends up including all of the accounts, including system accounts that I assume I shouldn't mess with.

So what's my best option here?

NOTE! When resetting passwords you also need to make sure to wipe anything extra from the ~/.ssh/authorized_keys file. Didn't remember this until after – thankfully I'd pretty much locked the servers down tightly and there was nothing in authorized_keys other than server-to-server stuff.

Best Answer

You can select the UIDs >= 500 to make sure you only get real users and not system accounts and then use the option --stdin of passwd to change the passowrd.

Something like this should work:

 while IFS=: read u x nn rest; do  if [ $nn -ge 500 ]; then echo "YOURSTRONGPASSWORD" |passwd --stdin $u; fi  done < /etc/passwd
Related Topic