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Date:      Thu, 10 Aug 2000 20:19:44 +0200 (CEST)
From:      Torbjorn Kristoffersen <sgt@netcom.no>
To:        freebsd-security@FreeBSD.ORG
Subject:   Re: suidperl exploit
Message-ID:  <Pine.BSF.4.21.0008102014330.1705-100000@hal.netforce.no>
In-Reply-To: <Pine.GSO.4.10.10008101904060.733-100000@nenya.ms.mff.cuni.cz>

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Hi Vladimir

If you type 'strings /usr/bin/suidperl | grep bin/mail' you'll get
	
/bin/mail root

Since /bin/mail is hardcoded into suidperl, and FreeBSD has its 'mail'
program in /usr/bin instead, you couldn't observe an effect.

I don't think there'll be a patch to this problem. Everyone should
instead download the recent version.

--
Torbjorn Kristoffersen
sgt@netcom.no
Digiweb Norway A/S

On Thu, 10 Aug 2000, Vladimir Mencl, MK, susSED wrote:

> 
> 
> I just came over the suidperl + mail vulnerability in Linux, and I was
> wondering whether it would work in FreeBSD.
> 
> (See http://www.securityfocus.com/bid/1547 for reference)
> 
> When I tried the exploit, no effect could be observed. However,
> significant part of the exploit lies in the undocumented feature of
> /bin/mail program - interactive behavior and interpretation of ~!
> sequences, even for stdin not a tty, when the "interactive" environment
> variable is set.
> 
> The second part of the exploit is in the fact, that, when the suid
> script dev+inode# identification changes, suidperl reports it to root by
> emailing in a very insecure manner - executing bin/mail in exactly the
> same environment as user provided for running suidperl - and passing the
> "interactive" variable.
> 
> On FreeBSD, I've not observed the reporting email even after a fair
> amount of time devoted to cause the race-condition.
> 
> 
> Either because I've not succeeded in causing it, or because suidperl
> avoids reporting the issue.
> 
> 
> I've not found any security advisory regarding this - can anybody
> comment on this? Has there be a silent fix to this?
> 
> 
> 
> 		Thanks
> 
> 			Vlada
> 
> 
> 
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