Re: Strange command histories in hacked shell history
From: Bill Vermillion (bv_at_wjv.com)
Date: Fri, 17 Dec 2004 21:25:56 -0500 To: firstname.lastname@example.org
Deep in the forest in the dark of night on Fri, Dec 17, 2004 at 20:11
with a cackle and an evil grin Elvedin Trnjanin cast another eye of
newt into the brew and chanted:
> Bill Vermillion wrote:
> >Can anyone explain why su does not use the UID from the login
> >instead of the EUID ? It strikes me as a security hole, but I'm no
> >security expert so explanations either way would be welcomed.
> Because su does exactly what is says. From the manual -
> *su* requests the password for /login/ and switches to that user and
> group ID
> after obtaining proper authentication.
I understand that after using Unix for about 2 decades.
However in FreeBSD a user is supposed to be in the wheel group [if
it exists] to be able to su to root.
But if a person who is not in wheel su's to a user who is in wheel,
then they can su to root - as the system sees them as the other
user. This means that the 'wheel' security really is nothing more
than a 2 password method to get to root.
If the EUID of the orignal invoker is checked, even if they su'ed
to a person in wheel, then they should not be able to su to root.
I'm asking why is this permitted, or alternatively why is putting a
user in the wheel group supposed to make things secure, when in
reality it just makes it seem more secure - as there is only one
more password to crack.
> *sudo* allows a permitted user to execute a /command/ as the superuser
> or another user, as specified in the /sudoers/ file. The real and
> effective uid and gid are set to match those of the target user as
> specified in the passwd file and the group vector is initialized based
> on blah blah blah...
And I use this for about two people who need extra levels to do
certain things for their web sites.
-- Bill Vermillion - bv @ wjv . com _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-security To unsubscribe, send any mail to "firstname.lastname@example.org"