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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Cisco, haven't we learned anything? (technician reset)y
In message <[email protected]>, eric writes: > >On Thu, 2006-01-12 at 21:05:52 -0500, Steven M. Bellovin proclaimed... > >> >> How much entropy is there in a such a serial number? Little enough >> that it can be brute-forced by someone who knows the pattern? Using >> some function of the serial number and a vendor-known secret key is >> better -- until, of course, that "secret" leaks. (Anyone remember how >> telephone credit card number verification worked before they could do >> full real-time validation? The Phone Company took a 10-digit phone >> number and calculated four extra digits, based on that year's secret. >> Guess how well that secret was kept....) >> > >Hi Steven, > >I believe the Netscreen default password of a serial number can only be >entered over the console (and possibly modem/aux) port(s). > That works for me. But note William Leibzon's issue: That works too and is most secure way. But its often enough that small offices would not have person who can fix the system and its not always possible to get network guy to come in right a way. It is good for those cases to be able to ask somebody onsite to just look at the back and dictate the serial# by phone. If you have physical access, the root password matters a lot less (and if it's the serial number, the local attacker can just peer at the back). If you need secure remote access -- well, it's not easy with clueless local administrators. But there's much less excuse for clueless developers, like the ones who created the login/password pair that started this thread -- credentials that, according to one posting, are acceptable for remote access. --Steven M. Bellovin, http://www.cs.columbia.edu/~smb
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