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Date: Tue, 26 Nov 2013 02:42:00 +0100
From: magnum <john.magnum@...hmail.com>
To: john-users@...ts.openwall.com
Subject: Re: Questions and suggestions to build a home cracking
box. :)
On 2013-11-25 22:16, Richard Miles wrote:
> On Fri, Nov 22, 2013 at 3:00 PM, magnum <john.magnum@...hmail.com> wrote:
>> On 2013-11-22 18:24, Richard Miles wrote:
>>> Aaa0?
>>> Aaa1?
>>> Aaa2?
>>
>> The mask, separated by position, is ?u ?l [ab] ?d ??
>>
>> First position is ?u == upper-case A-Z
>>
>> Second position is ?l == lower-case a-z
>>
>> Third position is [ab] == 'a' or 'b' (not supported by HC afaik)
To be clear I meant this very syntax is not supported in Hashcat but you
can do the same in other ways.
>> Fourth position is ?d == digit 0-9
>>
>> Fifth position is actually a static '?' but since the mask tokens begin
>> with a question mark, a literal one is escaped as '??'.
>
> Interesting. But where can I find a list of all these "meneumonics"? I see
> that some parts looks like regular expression as [ab], but the others for
> sure must have a kind of map with description about what they mean, right?
http://hashcat.net/wiki/doku.php?id=mask_attack#built-in_charsets
http://hashcat.net/wiki/maskprocessor
In JtR it's poorly documented (if at all) and code hasn't even settled
yet. Noone wrote the doc/MASK yet so "use the source, Luke" and in
particular rpp.c.
The rules engine, or rather its preprocessor, was reused for quickly
implementing mask mode. See doc/RULES but do not misread the "Character
classes" section as masks - only read the preprocessor section. Without
adding the new mnemonics you'd have to write the mask above as
"[A-Z][a-z][a-z][0-9]??".
The current mnemonics (defined in rpp.c line 108 and on) are just
shortcuts for predefined masks (?l really *becomes* [a-z] after
parsing). They are mostly shared with HC but we also have ?A as full
printable 8-bit (0x20-0xFF). Hashcat's maskprocessor defines ?h as
0xC0-0xFF while we currently define it as 0x80-0xFF. Maybe we should
change this and use ?h for 0xC0-0xFF and ?H for 0x80-0xFF, for closer
mimicing HC.
> But how the GPU will know where to "insert" the word from my wordlist?
>
> For example, what syntax may I use to say that my word (obtained from
> wordlist) will be prepend or append by this?
>
> Is there a "menumonic" to represent the "word" from wordlist? For example:
>
> --mask='?u?l[ab]?{w}?d??'
>
> Resulting in:
>
> AaaMyWord0?
> AaaMyWord1?
> AaaMyWord2?
I suggested a similar thing but it's not yet implemented. I haven't
tested current mask mode with wordlist so I'm not sure if Sayanyan's
current code always appends mask after word or if it can do something else.
> Also, is it possible to do more powerful mutation? For example, replace
> just the first occurrence of e with 3? replace only the second occurrence
> of e with 3? and so on until replace all occurrences of e with 3?
That is better achieved (and currently possible) using rules. Read
doc/RULES several times and try to understand the supplied rules in
john.conf ;-)
BTW I think Hashkill should also be mentioned. I'm pretty sure it too
outperforms JtR with GPU and it's open source:
http://www.gat3way.eu/hashkill/index.php
magnum
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