Newsgroups: comp.unix.admin
Path: utzoo!utgpu!jmason2
From: jmason2@gpu.utcs.utoronto.ca (Jamie Mason)
Subject: Re: dot in path (was Re: Mysterious security hole)
Message-ID: <1991Jun20.023256.12713@gpu.utcs.utoronto.ca>
Organization: University of Toronto Computer Services Advisor
References: <91161.131540SCHDAVZ@YaleVM.YCC.Yale.Edu> <70@pyuxf.UUCP> <319@dlss2.UUCP> <22940@ogicse.ogi.edu> <1991Jun19.191124.20380@cs.utk.edu>
Date: Thu, 20 Jun 1991 02:32:56 GMT

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.
>The user explains that when he updates a file, make fails to rebuild
>everything it should.  The admin scans the Makefile, does an ls or
>two, touches some files, checks the date, etc.  Of course, he's
>careful not to run "make" or the user's program, and he's left dot out
>of his path.  Eventually, he sees that a filename is mispelled, or
>that there's a missing dependency, or whatever.  The user thanks him,
>and that's that.  Right? 
>
>Unless the admin happened to mistype "date" as "dtae" at some point.

	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.

	In fact only *ever* execute commands as root that you really
*have to*.  Su to an appropriate, weaker, userid to do anything else.
AND put "." last in the path, if at all.

Jamie  ...  Lurker in the Process Table
Written On  Wednesday, June 19, 1991  at  10:29:38pm EDT