RE: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-12 Thread Clausen, Martin (DK - Copenhagen)
; cryptography@metzdowd.com; [EMAIL PROTECTED] 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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-12 Thread Ben Laurie
On Tue, Aug 12, 2008 at 9:55 AM, Clausen, Martin (DK - Copenhagen) [EMAIL PROTECTED] wrote: 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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-09 Thread Ben Laurie
Hal Finney wrote: I thought of one possible mitigation that can protect OpenID end users against remote web sites which have not patched their DNS. OpenID providers who used weak OpenSSL certs would have to change their URLs so that their old X.509 CA certs on their old URLs no longer work on

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Eric Rescorla
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

RE: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Dave Korn
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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Eric Rescorla
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

RE: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Leichter, Jerry
On Fri, 8 Aug 2008, Dave Korn wrote: | 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? Since the list of bad

RE: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Dave Korn
Eric Rescorla wrote on 08 August 2008 17:58: 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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Ben Laurie
On Fri, Aug 8, 2008 at 5:57 PM, Eric Rescorla [EMAIL PROTECTED] 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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Dan Kaminsky
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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Peter Gutmann
Eric Rescorla [EMAIL PROTECTED] writes: 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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Perry E. Metzger
Ben Laurie [EMAIL PROTECTED] writes: 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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Eric Rescorla
At Fri, 08 Aug 2008 10:43:53 -0700, Dan Kaminsky wrote: Eric Rescorla wrote: 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

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Nicolas Williams
On Fri, Aug 08, 2008 at 02:08:37PM -0400, Perry E. Metzger wrote: The kerberos style of having credentials expire very quickly is one (somewhat less imperfect) way to deal with such things, but it is far from perfect and it could not be done for the ad-hoc certificate system https: depends on

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Nicolas Williams
On Fri, Aug 08, 2008 at 11:20:15AM -0700, Eric Rescorla wrote: At Fri, 08 Aug 2008 10:43:53 -0700, Dan Kaminsky wrote: Funnily enough I was just working on this -- and found that we'd end up adding a couple megabytes to every browser. #DEFINE NONSTARTER. I am curious about the

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Paul Hoffman
At 1:47 PM -0500 8/8/08, Nicolas Williams wrote: On Fri, Aug 08, 2008 at 02:08:37PM -0400, Perry E. Metzger wrote: The kerberos style of having credentials expire very quickly is one (somewhat less imperfect) way to deal with such things, but it is far from perfect and it could not be done

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Leichter, Jerry
| Funnily enough I was just working on this -- and found that we'd | end up adding a couple megabytes to every browser. #DEFINE | NONSTARTER. I am curious about the feasibility of a large bloom | filter that fails back to online checking though. This has side | effects but perhaps

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Tim Dierks
[Sorry for duplicates, but I got multiple requests for a non-HTML version, and I didn't want to fork the thread. Also sorry for initially sending HTML; I didn't realize it was so abhorrent these days. ] On Fri, Aug 8, 2008 at 1:43 PM, Dan Kaminsky [EMAIL PROTECTED] wrote: It's easy to compute

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Ben Laurie
On Fri, Aug 8, 2008 at 7:54 PM, Tim Dierks [EMAIL PROTECTED] wrote: Using this Bloom filter calculator: http://www.cc.gatech.edu/~manolios/bloom-filters/calculator.html , plus the fact that there are 32,768 weak keys for every key type size, I get various sizes of necessary Bloom filter,

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Nicolas Williams
On Fri, Aug 08, 2008 at 12:35:43PM -0700, Paul Hoffman wrote: At 1:47 PM -0500 8/8/08, Nicolas Williams wrote: On Fri, Aug 08, 2008 at 02:08:37PM -0400, Perry E. Metzger wrote: The kerberos style of having credentials expire very quickly is one (somewhat less imperfect) way to deal with such

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Eric Rescorla
At Fri, 8 Aug 2008 15:52:07 -0400 (EDT), Leichter, Jerry wrote: | Funnily enough I was just working on this -- and found that we'd | end up adding a couple megabytes to every browser. #DEFINE | NONSTARTER. I am curious about the feasibility of a large bloom | filter that fails back

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Leichter, Jerry
| You can get by with a lot less than 64 bits. People see problems | like this and immediately think birthday paradox, but there is no | birthday paradox here: You aren't look for pairs in an | ever-growing set, you're looking for matches against a fixed set. | If you use 30-bit hashes -

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Florian Weimer
* Eric Rescorla: Why do you say a couple of megabytes? 99% of the value would be 1024-bit RSA keys. There are ~32,000 such keys. There are three sets of keys, for big-endian 32-bit, little-endian 32-bit and little-endian 64-bit. On top of that, openssl genrsa generates different keys

Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

2008-08-08 Thread Hal Finney
[I feel a little uncomfortable replying with such a wide distribution!] Getting browsers, or OpenID installations, to check CRLs or use OCSP to check for freshness is likely to be slow going. At this point I think the momentum still favors fixing the remaining DNS systems that are vulnerable to