Date: Mon, 23 May 2005 14:14:39 -0400 From: "James" <james@...nderdomesystems.com> To: <john-users@...ts.openwall.com> Subject: RE: Fastest Crack of known password length Kind of hard to reset Root ;) As far as big wordlist I've tried that one and let it run forever it seems (over a week) and since I am pretty sure the password is not word based it was unable to crack it. This is why I was thinking of an incremental against a known length of 8. One PC was set to incremental the other wasn't. Wasn't sure which would get there first. As far as running it against a single user hash all the users (well all but a few) have the same hash including root. I figured by setting it to work just that one hash again it would run a bit faster. This is somewhat a test to compare various attacks against passwords. Knowing a Windows sam file takes just minutes to crack 90% of the time because of weak passwords I wanted to see what John could do against a harder Linux password file so I got one where I don't know the password so I can't cheat by being creative in a wordlist. -----Original Message----- From: Solar Designer [mailto:solar@...nwall.com] Sent: Monday, May 23, 2005 12:12 PM To: john-users@...ts.openwall.com Subject: Re: [john-users] Fastest Crack of known password length James, On Tue, May 17, 2005 at 08:51:36AM -0400, James wrote: > What is the fastest method of cracking a password of known length > where the password is: > > 1. Linux Shadow file > 2. DES > 3. Mostly likely is not word based and includes at least 1 standard > keyboard character. > 4. Of a known length or at least do a progressice crack where I try 8, > that fails then I'll try 9, etc. You need to realize that the traditional crypt(3) DES-based hashes truncate passwords longer than 8 characters. So even if you think that your password is longer, it really is not. It should be quick enough to run through a wordlist with mangling rules for just a single traditional DES-based hash, so you do not need to apply any length restrictions there. Just pick a large enough wordlist (such as the "all.gz" available off ftp.openwall.com) and do: ./john -w=all.lst -rules pwfile Then proceed with "incremental" mode. You specify the known length by setting the MinLen and MaxLen parameters to it. That's done in a section such as "[Incremental:All]", which you may copy under a different name and customize. Then pass the new name from the command line, such as: ./john -i=custom pwfile Where the custom section is: [Incremental:Custom] File = $JOHN/all.chr MinLen = 8 MaxLen = 8 CharCount = 95 (the "$JOHN/..." syntax is for a 1.6.x development version). > I'm running > > john -users:***** -format:DES pwl That's fine. Please be sure to use a recent development version and build it with support for MMX or AltiVec (if you're on x86 or PPC) for a significant speedup. You shouldn't have to specify the "format" explicitly, although your doing so doesn't hurt. > Right now on one PC and > > john -users:***** -format:DES -i:ALL pwl > > On another. This doesn't make sense. You have both PCs do the same thing. > I've edited the ini to sent all min. lengths to 8 but does that do > what I think? Yes, perhaps (depending on what you think it does, of course). Why are you running John against a single password hash, though? Maybe it'd be simpler to reset the password? -- Alexander Peslyak <solar at openwall.com> GPG key ID: B35D3598 fp: 6429 0D7E F130 C13E C929 6447 73C3 A290 B35D 3598 http://www.openwall.com - bringing security into open computing environments
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