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Whilst following an online guide on how to secure Ubuntu server, I ran this command on one of my test VM's. 

sudo dpkg-statoverride --update --add root admin 4750 /bin/su

I know the intention of the command was to limit the use of su to specific users.
What I didn't realise is that su is already disabled by default on Ubuntu.

Could someone tell me how to reverse it on Ubuntu 12.04?

I have already tried:

sudo dpkg-statoverride --remove /bin/su
Touff
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    If it's disabled by default, and it's still disabled, then what's the problem? That command will have changed permissions on `/bin/su` to setuid root, admin group read/execute. That doesn't do much harm. If you want top open it up, `chmod g+rx /bin/su` will do that. If you want to lock it down, `chmod 0 /bin/su` will do that. – Sobrique May 29 '14 at 15:30

1 Answers1

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I've got satisfied with the following approach to disable su (tested in Lubuntu 14.10).

Open file /etc/pam.d/su. Then uncomment line:

# auth       required   pam_wheel.so

After this nobody (except users which are in root group) can use su. But it is still possible to start root session using sudo su.

flaz14
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