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Bugtraq archives for 3rd quarter (Jul-Aug) 1995: Re: SECURITY HOLE: FormMail

Re: SECURITY HOLE: FormMail

Neil Woods (neillegless.demon.co.uk)
Sat, 5 Aug 1995 10:26:35 +0100 

>
> | Just to be helpful, the way to do it more safely, without massive
> | need for checking is to build a complete mail message, including
> | header, and hand that to "sendmail -t" which then reads the recipient
> | information out of the constructed header.  [Sendmail should of course
> | be an invocation of smail or pp, not the BSD program of that name,
> | given the history of problems that has had]
>
> I suspect this still wont take care of emails to pipes or files,
> i.e  <|/bin/sh> or </.rhosts>, it is a legitimate, albeit unexpected,
> mail-command going to sendmail. So unless these two mode are totally
> stripped out of the sendmail, there will exist a vulnerability there,
> wont it?
>

No current version of sendmail (v8.*, any vendor supplied version) will
allow mailing directly to programs or files.  In order to deliver mail to
a program or file, it must be indirect (ie. alias expansion, or from a
users .forward file).

Cheers,

Neil
--
Let the Mystery Be, So Watcha Want, Longing In Their Hearts, Hate My Way,
M-Bike, Safari, Uncle June and Aunt Kiyoti, Daisy Dead Petals, Tuff Gnarl.

     ...like a badger with an afro throwing sparklers at the Pope...