Xref: utzoo comp.bugs.4bsd:896 comp.bugs.misc:178 comp.bugs.sys5:515
Path: utzoo!utgpu!attcan!uunet!husc6!purdue!umd5!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.bugs.4bsd,comp.bugs.misc,comp.bugs.sys5
Subject: Re: Hard Links between UNIX Utility Programs
Keywords: unix links bsd sysv sys5
Message-ID: <12824@mimsy.UUCP>
Date: 4 Aug 88 12:14:12 GMT
References: <184@chip.UUCP> <185@chip.UUCP> <218@tarkus.UUCP> <153@ispi.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 20

In article <153@ispi.UUCP> jbayer@ispi.UUCP writes:
>Another workable solution is ... [to:]
>Create a shell script ....
>Make the shell script executable by everyone.
>Make the owner of the shell script the super user
>Set the user bit for the shell script (chmod u+s name)

Setuid scripts are not available in vanilla System V.

Setuid shell scripts are a security hole in vanilla BSD.  If you have
not either made extensive kernel changes, or else installed the fix
from Berkeley that simply disables set-ID scripts, and you make a
setuid shell script (for either sh or csh), I can become that user on
your machine given access to any ordinary user account.  I am not
willing to publish the method here; I will say that disabling setuid
scripts in the kernel, or simply not creating them in the first place,
suffices to prevent this avenue of attack.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris