[nsp-sec] Debian to disclose critical bug on Tuesday

[Florian Weimer]

Hi,

This is just a heads-up that Debian will publish an advisory about a
critically flawed random number generator in OpenSSL on Tuesday, May
13 2008 (1200 UTC, to be precise).  Debian OpenSSL versions since
0.9.8b-1 are affected (including the one in etch), up to and excluding
0.9.8g-9 (already in testing/lenny).

I'm posting this here because one of the applications that is affected
is OpenSSH.  As a result of the bug in OpenSSL, there is only a
comparatively small number of OpenSSH host and user keys.  So if you
use Debian on your workstation, have generated a new user key since
May 2006, and use that to authenticate to some routers, and those
routers offer SSH service to the general public, you've got a problem.
Sorry about that. 8-(

Practically everything doing cryptography on Debian systems is
affected, with the exception of GnuPG and GNUTLS- and NSS-based
software (which includes Exim and Iceweasel né Firefox).  DNSSEC keys,
Tor keys, OpenVPN keys, the list is pretty long.  It's also possible
to recover session keys of past OpenSSL-encrypted sessions.  For
DNSSEC keys and OpenSSL-generated X.509 certificates, there is a
slightly higher amount of entropy, but not by much.  But OpenVPN keys
are rather easily predicted, too.

Network activity to watch for is OpenSSH scans, as usual.  But there's
a twist because attackers will eventually pick up the key list (yes,
it's that small, we're currently discussing if we're going to disclose
the key fingerprints along with the initial advisory), and try
public-key authentication instead of password guessing.  So if you see
that in your logs, I'd be interested to know that.

Please treat the contents of this message confidential until the
different aspects of the bug have become public knowledge (first and
foremost, its existance, but also the fact that it's possible to build
a key list, which is not immediately obvious).

Florian
-- 
Florian Weimer                <fweimer at bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99