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Article View: comp.security.misc
Article #102

Re: Big Dictionary Searches (Was: Re: Problem with npasswd??)

#102
From: Doug Siebert
Date: Thu, 06 Aug 1992 01:43
34 lines
2435 bytes
In article <3947@moscom.UUCP> jgp@moscom.com (Jim Prescott) writes:
>
>Knowing where the binary search finished would tell a cracker the first
>few characters of the actual password, greatly reducing the search space.
>
>If they can snoop NFS packets off the ethernet they can learn this
>directly.  If they can login to either the NFS server, or the client
>where the password change took place, it might also be possible to
>figure it out by the doing timed reads on the bigdict.sorted file
>and intuiting which reads were satified from the buffer cache and
>which required physical I/O.

If they can snoop NFS packets off the ethernet presumably they can sniff ALL
packets off the Ethernet.  Then the cracker would be better served by snooping
the packets generated by the user typing in his/her prospective password (it
is even done TWICE!) than by snooping through NFS packets and trying to piece
together the password in such a manner.

Let's face it, if a cracker has access to all packets on your ethernet, a
security measure like npasswd isn't going to be a bit of good, no matter how
it is done.

I'm not so sure about the timed read method, but it sure sounds unduly
difficult and unrealiable.  Does anyone know if this method would even be
possible?

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Technical Details
Message-ID: <1992Aug6.014352.16136@news.uiowa.edu>
Path: arc1-ca.pugleaf.net!sparky!uunet!cis.ohio-state.edu!zaphod.mps.ohio-state.edu!moe.ksu.ksu.edu!hobbes.physics.uiowa.edu!news.uiowa.edu!icaen.uiowa.edu!dsiebert
References: <3947@moscom.UUCP>

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Newsgroups: comp.security.misc,alt.security
Path: arc1-ca.pugleaf.net!sparky!uunet!cis.ohio-state.edu!zaphod.mps.ohio-state.edu!moe.ksu.ksu.edu!hobbes.physics.uiowa.edu!news.uiowa.edu!icaen.uiowa.edu!dsiebert
From: dsiebert@icaen.uiowa.edu (Doug Siebert)
Subject: Re: Big Dictionary Searches (Was: Re: Problem with npasswd??)
Sender: news@news.uiowa.edu (News)
Message-ID: <1992Aug6.014352.16136@news.uiowa.edu>
Date: Thu, 6 Aug 1992 01:43:52 GMT
References: <3947@moscom.UUCP>
Nntp-Posting-Host: l_cae14.icaen.uiowa.edu
Organization: ISCA
Keywords: dictonary time lookups
Lines: 34