For some reason, when I try to run any programs (I am trying to run a rootkit hunter: rkhunter) as root on the command line with sudo like this:

sudo rkhunter

Then I get this message:

You must be the root user to run this program

and then I get these lines:

sudo: error in /etc/sudo.conf, line 0 while loading plugin 'sudoers_policy'
sudo: /usr/lib/sudo/sudoers.so must only be writable by owner
sudo: fatal error, unable to load plugins

I try typing in just sudo but that comes up with the same three errors as above. Also in /etc/ sudo.conf does not exist.

I cannot run any other programs as root through sudo. It was also strange because I could run as root a day ago. I would like it to work.
Just so you know, I am the only user of this computer, and the administrator, running Lubuntu 14.04.1.

2 Answers 2


If you can login as root:

$ su root     #enter password
$ chmod 644 /usr/lib/sudo/sudoers.so
$ chown -R root /usr/lib/sudo

If not, you'll have to startup in recovery mode, get write permission on your disk, and change the mode of that file. https://wiki.ubuntu.com/RecoveryMode

$ mount -o remount,rw /
$ chmod 644 /usr/lib/sudo/sudoers.so
  • I'm using a headless raspberry pi - how would I start in recovery mode without a keyboard or monitor?
    – Big Money
    Jun 15, 2019 at 20:46
  • Doesn't it have a sdcard that you easily can adjust on your desktop/laptop? Jun 17, 2019 at 0:36
  • It does have an sdcard, good thinking, I can just plug it in and boot from there
    – Big Money
    Jun 17, 2019 at 20:20
  • 2021, still works :) May 3, 2021 at 19:47

1st open your terminal then type and enter

pkexec su

it will log you in as a root user

now type (replace username with your PC's username):

chown -R username /usr/lib/

now open file explorer and goto /usr or type this in another terminal: nautilus /usr

now, right click on the lib folder and goto 'Permissions' tab.

From there change the access of 'Group' and 'Others' to- 'Access files'

now click on the button 'Change Permissions for Enclosed Files' now change the access of 'Group' and 'Others' to- 'Access files' or 'Read-only'.

now close that window and return to the terminal(the one with root user).

now type

chown -R root /usr/lib/


now you can use sudo again.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.