UNIX for Dummies Questions & Answers

You guys gave me an idea with su, why let everyone run 'su' when only the users in the group 'wheel' should be able to run it.
I set su to the following permissions

-r-sr-s--- 1 root wheel 16384 Apr 13 17:08 /usr/bin/su*

(this is on openbsd 3.1 with a custom kernel)
I also had to chown root.wheel to allow people in the 'wheel' group to access 'su'. The default was root.bin.
Here are the following results;

uid=1004(taso) gid=1004(taso) groups=1004(taso)
bash-2.05$ su
bash: /usr/bin/su: Permission denied

and with a user in the wheel group;


uid=1000(crispexi) gid=1000(crispexi) groups=1000(crispexi), 0(wheel)
bash-2.05$ su
Password:
bash-2.05#

The way I set permissions;

chmod 6550 /usr/bin/su
chown root.wheel /usr/bin/su

and you're done.

crispexi,

That may be okay for you. However, I only have 2-4 people who need su for root to my boxes. For me that is just one more file to manage which I don't have time to manage.

I can imagine one bad scenario. In an environment that allows users to have a regular password, that type of setup can be jeopardized to gain access to root, if someone gains access to another user's password. Also, I believe that granting group permissions are considered by some to be another possible security breach.

My situation is very restrictive, such that we use one-time password at the user level and less than 5 people have root su privileges, so I don't need to manage another file for only 5 users. Also, we have standards that don't allow us to change permissions on executables that can be considered a security hole.

How many people have root that you would need to create such a file? And why do so many people have root access?

root is privileged for a reason. I hope you trust all of those people implicitly.

The bottom line is if this works for you, great. Just remember, in most cases your scenario is not feasible.

>How many people have root that you would need to create such >a file? And why do so many people have root access?

only i have root and i didn't create any files i just modified permissions to 1 executable. You can't login as root remotley and i mostly login to that box remotley and only use it locally sparingly.

I use an AIX 4.3.3 box. root can only log in from the terminal.
The only way to get to root remotely is to log in using my id and su root. No other person can su root or log in to root remotely. With AIX there is an su log file that lists all attempt to su another id. When root logs in my ID is sent mail indicating the time and port of the login. Therefore I know if root is compromised. I then can search the su log files to see who attempted or sucessfully cracked my root password.

Ditto with epdgesell. couldn't say it better.

If you only have a few users, what was all that discussion about creating a root.wheel? Was that just for general consumption?


I thought that was your real environment. In any case, my opinion still stands for hypothetical cases regarding root access.

su has default of root.bin where i just chown'd it to root.wheel because i didnt feel like adding myself to the bin group heh

there was no file creation, i just used chmod and chown everything else was left at default values