From: Michael Handler <grendel@netaxs.com>
Date: Fri, 30 Sep 94 02:44:19 PDT
To: Alan Barrett <barrett@daisy.ee.und.ac.za>
Subject: Re: PGP hole
In-Reply-To: <Pine.3.89.9409301126.C1189-0100000@daisy.ee.und.ac.za>
Message-ID: <Pine.SUN.3.90.940930053444.11908A-100000@unix3.netaxs.com>
MIME-Version: 1.0
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On Fri, 30 Sep 1994, Alan Barrett wrote:

> > The bug seems to be present in all versions (even the ViaCrypt versions
> > have this problem). It has been reported as a bug to the MIT pgp-keepers.
> 
> The "bug" looks like a deliberate design decision to me.  Everything from
> the "--- BEGIN PGP" line to the first blank line is ignored, and is not
> considered part of the signed message.  There's a comment in the source
> code (file armor.c in the versions I checked), saying "Skip header after
> BEGIN line". 

	Yes, this was a deliberate design decision, most probably so the 
same code could be used to parse --- BEGIN PGP ENCRYPTED MESSAGE --- and 
--- BEGIN PGP SIGNATURE ---. However, this is a _huge_ security hole, as 
it allows the nearly-undetectable modification of PGP-signed messages.

Mike
--
Michael Handler                                         <grendel@netaxs.com>
PGP public key available                         1984: We're Behind Schedule
                 Civil Liberty Through Complex Mathematics