Bugtraq mailing list archives
Re: OpenID/Debian PRNG/DNS Cache poisoning advisory
From: "Stefan Kanthak" <stefan.kanthak () nexgo de>
Date: Sat, 9 Aug 2008 00:29:52 +0200
Dan Kaminsky wrote:
Eric Rescorla wrote:At Fri, 8 Aug 2008 17:31:15 +0100, Dave Korn wrote:Eric Rescorla wrote on 08 August 2008 16:06: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?Isn't that exactly what "Browsers must check CRLs" means in this context anyway? What alternative client-side blacklisting mechanism do you suggest?It's easy to compute all the public keys that will be generated by the broken PRNG. The clients could embed that list and refuse to accept any certificate containing one of them. So, this is distinct from CRLs in that it doesn't require knowing which servers have which cert...Funnily enough I was just working on this -- and found that we'd end up adding a couple megabytes to every browser.
At least for the weak keys kudos to Debian's OpenSSL maintainer there exists an extension to Firefox which checks the keys, see <http://codefromthe70s.org/sslblacklist.asp>, as well as c't's SSLguardian for the Windows Crypto API, see <http://www.heise-online.co.uk/security/features/111039/0> and <http://www.heise-online.co.uk/security/features/111039/1> Stefan
Current thread:
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory, (continued)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Dan Kaminsky (Aug 08)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Eric Rescorla (Aug 08)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Nicolas Williams (Aug 08)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Leichter, Jerry (Aug 08)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Eric Rescorla (Aug 08)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Forrest J. Cavalier III (Aug 12)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Leichter, Jerry (Aug 12)
- key blacklisting & file size (was: OpenID/Debian PRNG/DNS Cache poisoning advisory) Solar Designer (Aug 08)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Florian Weimer (Aug 12)
- Message not available
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Ben Laurie (Aug 08)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Stefan Kanthak (Aug 12)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Tim Dierks (Aug 12)
- RE: OpenID/Debian PRNG/DNS Cache poisoning advisory Leichter, Jerry (Aug 08)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Ben Laurie (Aug 12)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Ben Laurie (Aug 12)
- Re: OpenID/Debian PRNG/DNS Cache poisoning advisory Ben Laurie (Aug 12)