Can someone explain what is `<user> ALL=(ALL) NOPASSWD:ALL` does in sudoers file?

Question

I know that that line above allows <user> to run sudo command without having to type in the password. But what does the syntax actually mean? If you can link to an article then that would be fine too. Thanks

Solution

From man sudoers

By default, sudo requires that a user authenticate him or herself before running a command. This behavior can be modified via the NOPASSWD tag

So users or groups are able to run sudo without authenticating. This makes it a big security risk so be very careful with this command.

Also check https://askubuntu.com/questions/334318/sudoers-file-enable-nopasswd-for-user-all-commands

Comments

[enharmonic]

Does this answer your question? What do the "ALL"s in the line " %admin ALL=(ALL) ALL " in Ubuntu's /etc/sudoers file stand for?

[Nabeel Parkar]

Thanks. What about ALL:(ALL)? I know it has something to do about users and groups but I don't understand Linux groups as it is so if you can help me out, that would be awesome.

[Erjen Rijnders]

With that command, you just give ALL permissions. You must still authenticate.

[Erjen Rijnders]

If you mean the exact function of the ALL=(ALL:ALL) ALL. The first ALL is the users allowed, the second one is the hosts, the third one is the user as you are running the command, the last one is the commands allowed. Check: unix.stackexchange.com/questions/201858/…

[tetra]

The runas_spec and host_spec are switched here, it should be 'user_spec host_spec=(runas_spec) NOPASSWD:cmd_spec'