Re: [Full-disclosure] [OpenID] OpenID/Debian PRNG/DNS Cache poisoning advisory

[Peter Williams <pwilliams@xxxxxxxxxxxxx>]

Since openid is essentially a url resolver security design concept (assuming 
its not a native xri resolver case), openid2 does feels a bit more exposed to 
the consequences of particular construction they laid out. The whole mapping of 
"identity" via http - the heart of the openid concept -requires secure 
discovery. Because that is hard, the openid form of websso is interesting!

Surpised they didn't draw conclusions on hxri modes of xri resolution in 
openid2, which relies on https (as a resolver, not just a way of invoking a 
secure channel). An academic completeness oversight, really: failure to define 
the limits of the logic.

All Good news for openid2 tho - that reseach/academic folk *want* the 
pr/association with it (while hopefully addressing the usual prng-based flaws 
usually found in these kind of grassroots-based crypto communities)!

________________________________
From: Eddy Nigg (StartCom Ltd.) <eddy_nigg@xxxxxxxxxxxx>
Sent: Friday, August 08, 2008 6:46 AM
To: Ben Laurie <benl@xxxxxxxxxx>
Cc: security@xxxxxxxxxx <security@xxxxxxxxxx>; 
full-disclosure@xxxxxxxxxxxxxxxxx <full-disclosure@xxxxxxxxxxxxxxxxx>; 
bugtraq@xxxxxxxxxxxxxxxxx <bugtraq@xxxxxxxxxxxxxxxxx>; OpenID List 
<general@xxxxxxxxxx>; cryptography@xxxxxxxxxxxx <cryptography@xxxxxxxxxxxx>
Subject: Re: [OpenID] OpenID/Debian PRNG/DNS Cache poisoning advisory

Ben Laurie:

Security Advisory (08-AUG-2008) (CVE-2008-3280)
===============================================

Ben Laurie of Google's Applied Security team, while working with an
external researcher, Dr. Richard Clayton of the Computer Laboratory,
Cambridge University, found that various OpenID Providers (OPs) had
TLS Server Certificates that used weak keys, as a result of the Debian
Predictable Random Number Generator (CVE-2008-0166).

In combination with the DNS Cache Poisoning issue (CVE-2008-1447) and
the fact that almost all SSL/TLS implementations do not consult CRLs
(currently an untracked issue), this means that it is impossible to
rely on these OPs.


This affects any web site and service provider of various natures. It's not 
exclusive for OpenID nor for any other protocol / standard / service! It may 
affect an OpenID provider if it uses a compromised key in combination with 
unpatched DNS servers. I don't understand why OpenID is singled out, since it 
can potentially affect any web site including Google's various services (if 
Google would have used Debian systems to create their private keys).

Regards

Signer:         Eddy Nigg, StartCom Ltd.<http://www.startcom.org>
Jabber:         startcom@xxxxxxxxxxxx<xmpp:startcom@xxxxxxxxxxxx>
Blog:   Join the Revolution!<http://blog.startcom.org>
Phone:  +1.213.341.0390


_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/