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full-disclosure-uk: Re: [Full-disclosure] OpenID/Debian PRNG/DNS

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

From: Clausen, Martin (DK - Copenhagen) <mclausen_at_nospam>
Date: Tue Aug 12 2008 - 08:55:53 GMT
To: "Eric Rescorla" <ekr@networkresonance.com>, "Ben Laurie" <benl@google.com>


You could use the SSL Blacklist plugin
(http://codefromthe70s.org/sslblacklist.asp) for Firefox or heise SSL Guardian
(http://www.heise-online.co.uk/security/Heise-SSL-Guardian--/features/11 1039/) for IE to do this. If presented with a Debian key the show a warning.

The blacklists are implemented using either a traditional blacklist (text file) or distributed using DNS.

~martin

-----Original Message-----
From: owner-cryptography@metzdowd.com
[mailto:owner-cryptography@metzdowd.com] On Behalf Of Eric Rescorla Sent: 8. august 2008 17:06
To: Ben Laurie
Cc: bugtraq@securityfocus.com; security@openid.net; OpenID List; cryptography@metzdowd.com; full-disclosure@lists.grok.org.uk Subject: Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

At Fri, 8 Aug 2008 11:50:59 +0100,
Ben Laurie wrote:
> However, since the CRLs will almost certainly not be checked, this
> means the site will still be vulnerable to attack for the lifetime of
> the certificate (and perhaps beyond, depending on user behaviour).
> Note that shutting down the site DOES NOT prevent the attack.
>
> Therefore mitigation falls to other parties.
>
> 1. Browsers must check CRLs by default.

Isn't this a good argument for blacklisting the keys on the client side?

-Ekr



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