From owner-freebsd-questions  Mon Sep 24 19:22: 5 2001
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From: mcbrune <mcbrune@home.com>
Message-Id: <200109250221.f8P2LhK06485@home.com>
Subject: Re: chmod
In-Reply-To: <3BAFE35F.543E141A@home.com>
To: cyu0635@home.com
Date: Mon, 24 Sep 2001 21:21:43 -0500 (CDT)
Cc: Odhiambo Washington <wash@wananchi.com>,
	"freebsd-questions@FreeBSD.ORG" <freebsd-questions@FreeBSD.ORG>
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Well, that depends...

As a general rule, if SUID does not need to be set, as in the example below, then do not set it.

Sometimes the SUID needs to be set, as in /usr/bin/passwd, which allows people to change their password. 
The security hazard is when someone has executed the program with SUID, a person can try to overflow the buffer and either get a shell or execute some code as the owner of the program.


Hope this clears some things up.

Corey


> Hi
> 
> Is it any security problem? Please teach me.
> 
> Many thanks
> 
> 
> Odhiambo Washington wrote:
> 
> > * mcbrune <mcbrune@home.com> [20010924 05:37]: writing on the subject 'Re: chmod'
> > | It sets the SUID bit on the file. This will allow the executable to be run as
> > | the owner of the file. You can read the man page on chmod for more info.
> > |
> > |
> > | Corey
> > |
> > | > Hi all
> > | >
> > | > What is the meaning of the figure '4'?
> > | >
> > | >
> > | > chmod 4755 /usr/sbin/sendmail
> > | >
> > | > Many tks
> >
> > Hmm, why did you do it? ;-)
> >
> > -Wash
> >
> > --
> > Odhiambo Washington
> > Wananchi Online Ltd.,
> > wash@wananchi.com 1st Flr Loita Hse.
> > Tel: 254 2 313985 Loita Street.,
> > Fax: 254 2 313922 PO Box 10286,00100-NAIROBI,KE.
> >
> > It is always good policy to tell the truth unless of course you are an
> > exceptionally good liar.
> > -Jerome K. Jerome
> > (contributed by Chris Johnston)
> >
> >   ------------------------------------------------------------------------
> >    Part 1.2Type: application/pgp-signature
> 
> 
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