RE: Rainbow Tables

["Simpson, Brett" <Brett.Simpson () hsn net>]

> -----Original Message-----
> From: Tony Stark [mailto:stark192 () hotmail com] 
> Subject: Re: Rainbow Tables

Snip...

> Reason for this...the idea is that if we take the current 
> list of passwords 
> create a pre-computed hash table the next time we audit we'd 
> run LC5 (till I 
> convense them otehrwise) and all but the passwords that 
> changed and new 
> accounts would get knocked out right away.
>
> Does anyone have a hint as to how I should do this? Is there 
> a way to take 
> the hashes and the cracked clear text and merge them into a table?

http://www.antsight.com/zsl/rainbowcrack/

For non lan manager hashes this would require a tremendouse amount of
disk space (tera to peta bytes). Every password can have a large number
of salts (the exact number depends of the type of hash i.e. md5,
sha-1,etc). 

So let's say you have a UNIX system using the older crypt then you would
have 4096 salts that are possible per password. So for every clear text
version of a password you would have to store 4096 different salts. I
have an English dictionary I use with JtR so 411,563 words.. Then I use
rules mode and that number jumps to 15,773,164 (171MB). Now times that
by 4096 salts and you get 64,606,879,744 variations (700+ TB).

For Windows if your looking at the lanman hashes (not nt hashes) then
they only have one salt so it would be possible to generate a table on
common words and variations for only a couple hundred megabytes.

You should also read the teracrack article. 

http://security.sdsc.edu/publications/teracrack.pdf

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