Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!asuvax!ncar!elroy.jpl.nasa.gov!lll-winken!news.arc.nasa.gov!mindcraft.com!karish
From: karish@mindcraft.com (Chuck Karish)
Newsgroups: comp.unix.admin
Subject: Re: dot in path (was Re: Mysterious security hole)
Summary: su from root not safe
Message-ID: <677526078.470@mindcraft.com>
Date: 21 Jun 91 17:41:17 GMT
References: <91161.131540SCHDAVZ@YaleVM.YCC.Yale.Edu> <70@pyuxf.UUCP> <319@dlss2.UUCP> <22940@ogicse.ogi.edu> <1991Jun19.191124.20380@cs.utk.edu> <1991Jun20.023256.12713@gpu.utcs.utoronto.ca>
Organization: Mindcraft, Inc.
Lines: 24

In article <1991Jun20.023256.12713@gpu.utcs.utoronto.ca>
jmason2@gpu.utcs.utoronto.ca (Jamie Mason) writes:
|In article <1991Jun19.191124.20380@cs.utk.edu| Dave Sill <de5@ornl.gov| writes:
||Now suppose the user calls up the system administrator, who is known
||to remain su'd to root most of the time, and requests help with make...

|	Of course, the administator's mistake was *not* that he had "."
|in is path.  His mistake was that he helped a user with a problem with
|their personal files *as root*.  What he/she should have done is su'ed to
|the user with the problem, then used *that* shell to solve the problem.
|Remember that root can su to anyone *without* entering a password.  By
|poking around the user's files *AS THE USER*, there is no chance of
|accidentally executing something nasty as root.

I don't think this is true on systems that support saved-set-user-ID.
A Trojan horse program could su back to root under some circumstances.

It's often worth trying to reproduce a problem from several different
logins.  Problems caused by user environment settings can be
difficult to diagnose.
-- 

	Chuck Karish		karish@mindcraft.com
	Mindcraft, Inc.		(415) 323-9000