Date: Thu, 31 Jan 2013 07:59:52 +0400 From: Solar Designer <solar@...nwall.com> To: john-dev@...ts.openwall.com Subject: NetNTLMv1 magnum, all - Since I think you're not on Twitter: TTYtter> /th c9 zz0> (x13) <hashcat> Exploited a NetNTLMv1 weakness which made it as easy to crack as NTLM: http://t.co/Sul7VK1p - No, this is not what CloudCracker does zz1> <@thorsheim> @hashcat Another weakness first discovered by you? ;-)\n(if so; @dangoodin001 ...) zz2> <@hashcat> @thorsheim @dangoodin001 I discovered it myself and afterwards found it on jtr mailinglist. They never made any use of it /cc @solardiz zz3> <@thorsheim> @hashcat Perhaps a forum post on its implications? Speed improvements etc? / @solardiz zz4> <@hashcat> @thorsheim @solardiz Yeah why not. Will do it once I ported it to GPU. It will be far far to fast for such an important algorithm :-) I'm not sure what exactly atom is referring to. There's definitely lots of room for optimization of the code in JtR: http://www.openwall.com/lists/john-dev/2011/04/17/1 We could switch to using JtR's faster NTLM code, and bitslice DES code for the DES portion. This would probably provide speeds similar to hashcat's on that screenshot (76M c/s for NetNTLMv1 on one CPU chip), or maybe even better. (Looks like JtR's NTLM provides 22.6*8 = ~181M c/s on FX-8120 - that's --test speeds combined for 8 independent processes. Of course, actual cracking speed will be less.) However, maybe atom somehow reduced or eliminated the DES portion from the per-candidate loop, as I doubt he went for bitslice DES here. ;-) Curious. Oh, here's an idea: what if we apply the DES encryption (or decryption) to the last of the 3 blocks, not the first? Doesn't the last block contain only like a couple of non-zero bytes? (I don't recall.) If so, we could replace this instance of DES with a lookup table, computed just once (e.g. at program startup, to avoid increasing program size). Is this it? Was it mentioned on our mailing lists before? Maybe in the 2007 discussion with jmk, in rainbow tables context? Alexander
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