Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 05 Sep 2006 09:08:10 -0700
From:      Colin Percival <cperciva@freebsd.org>
To:        Mike Tancsa <mike@sentex.net>
Cc:        freebsd-security@freebsd.org
Subject:   Re: http://www.openssl.org/news/secadv_20060905.txt
Message-ID:  <44FDA0EA.5050409@freebsd.org>
In-Reply-To: <7.0.1.0.0.20060905105253.149db9a8@sentex.net>
References:  <7.0.1.0.0.20060905105253.149db9a8@sentex.net>

next in thread | previous in thread | raw e-mail | index | archive | help
Mike Tancsa wrote:
> Does anyone know the practicality of this attack ? i.e. is this trivial
> to do ?

I'm as surprised by this as you are -- usually I get advance warning about
upcoming OpenSSL issues via vendor-sec -- but on first glance it looks like
this attack is indeed trivial.

Also, it looks like the attack isn't limited to keys with a public exponent
of 3; unless I misunderstand the bug, it affects small exponents generally.
An exponent of 17 on a 4096-bit key is almost certainly vulnerable; beyond
that I would need to read the ASN code to confirm.

Keys with a public exponent of 65537 are absolutely not vulnerable to this
attack.

Colin Percival



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?44FDA0EA.5050409>