Date: Thu, 16 Dec 2010 00:44:51 +0300 From: Solar Designer <solar@...nwall.com> To: Jon Oberheide <jon@...rheide.org> Cc: john-users@...ts.openwall.com Subject: Re: JtR/OpenMP against Gawker passwords Jon, On Wed, Dec 15, 2010 at 04:16:03PM -0500, Jon Oberheide wrote: > Many of the initial results were from some large wordlists and mangling > rules. BTW, you could want to see: http://www.openwall.com/lists/john-users/2010/12/15/3 Maybe you did not try the custom .chr file "trick" (a .chr file based on your already cracked passwords)? > I know others have been using the OpenMP patches on the Gawker > set as well. I'll try to convince my buddy to provide some JtR OpenMP > benchmarks on his 64-way box. Please do! In fact, it'd be great for him to add an entry here: http://openwall.info/wiki/john/benchmarks > > Benchmarking: Traditional DES [128/128 BS SSE2-16]... DONE > > Many salts: 20465K c/s real, 2562K c/s virtual > > Only one salt: 16003K c/s real, 1999K c/s virtual > > For reference, the benchmarked machine was a x86_64 Gentoo box with gcc > 4.5.1. Thanks! You could add that info to the wiki page above, too. I did benchmark a very similar machine, but it was under some unrelated load at the time. > > Apparently, this was with 1.7.6-omp-des-7. The slightly older > > 1.7.6-omp-des-4 patch, also available on the wiki, would do slightly > > better at "many salts" (relevant for the run against Gawker hashes), but > > a lot worse at "only one salt" (irrelevant in this case). > > Ah, nice, I didn't realize -4 was more effective on many-salts. I've just added a clarification to the wiki. > I could run the benchmarks with that patch if that would be desirable. That's up to you. > > It's also curious how the Gawker hashes have only 3844 different salts. > > Normally, for this number of hashes all possible salts would be present - > > that is, there would be exactly 4096 different salts. This suggests a > > poor random number generator, which in turn suggests that of the 3844 > > salts some likely correspond to a lot more hashes than some others. Thus, > > a more efficient attack could be mounted on a large subset of the hashes > > (but a much smaller subset of the salts) by using the "--salts" option. > > I found that very curious as well. I haven't dug into the Gawker's > leaked source code to see what they're were actually using for a > PRNG/crypt. That would be curious to know, but you don't have to. You can just use "--salts" (adjust its parameter) to get more passwords cracked sooner. > > What did you mean by this Twitter comment, though - "Bad JtR, why did > > you forget to load up a third of the hashes? Grrrr..."? Is this some > > kind of usability issue for me to address? > > That was my fault not realizing I had resumed an previous run. I suppose > the status text could be more verbose in terms of session resuming, but > that was a human error! :-P Yeah, "verbose mode" is on my to-do list for JtR. There are many things it could warn/remind about. Thanks, Alexander
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.