Article View: comp.security.misc
Article #102Re: Big Dictionary Searches (Was: Re: Problem with npasswd??)
From: Doug Siebert
Date: Thu, 06 Aug 1992 01:43
Date: Thu, 06 Aug 1992 01:43
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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? -- /-----------------------------------------------------------------------------\ | Doug Siebert | "I don't have to take this abuse | | Internet: dsiebert@icaen.uiowa.edu | from you - I've got hundreds of | | NeXTMail: dsiebert@chop.isca.uiowa.edu | people waiting in line to abuse | | ICBM: 41d 39m 55s N, 91d 30m 43s W | me!" Bill Murray, Ghostbusters | \-----------------------------------------------------------------------------/ Hi, I'm a .signature worm. I've already copied myself into your .signature.
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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!dsiebertReferences:
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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