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

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 of

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 the

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 ca

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 depen

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 has

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 tha

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 w

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 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 comp

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 pe

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 fo

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 f

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

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

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

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 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 vulnerabl

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 n

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 mea

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 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 th

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

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 D