Unable to SU to root

The error “ -bash: /bin/su: Permission denied ” you get while trying to su to root after logged as sudo because of the incorrect permission of “ /bin/su “. Make sure you have given correct permission as follows:


# chmod 4750 /bin/su
# ll /bin/su
-rwsr-x— 1 root wheel 24312 Mar 21 2012 /bin/su*

If the problem still exists, check if the sudo user has been added as wheel user in the server. Check it in the file /etc/group like as follow:

wheel::10:root,sudouser (..sudouser should be replaced with correct sudo username)

In case you have no backend access, you can login to WHM and add wheel user there Home »
Security Center »
Manage Wheel Group Users
then choose sudo user from list and click “ Add to Group “.