Bugtraq mailing list archives
Re: S/Key & OPIE Database Vulnerability
From: stevev () HEXADECIMAL UOREGON EDU (Steve VanDevender)
Date: Wed, 26 Jan 2000 11:53:05 -0800
Mudge writes:
Given that you know what machine you are connecting to, the use of the seed in the S/key challenge is not as necessary to present to the end user as it might be otherwise. Thus - server: abc123 challenge: s/key 99 K113356 could be reduced to server: abc123 challenge: s/key 99 as presented to the user. This would make the current dictionary attacks largely unusable as there is a secret that is required but unknown to the attacker. The original version of s/key that I had modified to run on the L0pht machine did just that (sorry folks, the software was long blown away - though hobbit has a niced moded version of s/key on ftp://avian.org I believe). If you can get to this point, then it makes all the sense in the world to not have the /etc/skeykeys file world readable.
Initially I thought this meant removing the seed entirely from S/Key. Mudge clarified this to me by explaining that what he meant was removing the routine presentation of the seed in the login challenge, but continuing to use it internally. It would still be necessary to present a new seed in the process of renewing one's S/Key sequence, so while the seed is still exposed, the amount of repeat exposure would be significantly reduced. This is at least quite a bit better than what I thought he meant before. Ultimately I wonder how much of a future S/Key has now that SSH and similar utilities are widely deployed and provide much more sophisticated protections, especially session encryption.
Current thread:
- S/Key & OPIE Database Vulnerability, (continued)
- S/Key & OPIE Database Vulnerability harikiri (Jan 21)
- Re: S/Key & OPIE Database Vulnerability David Maxwell (Jan 23)
- S/Key & OPIE Database Vulnerability Steve VanDevender (Jan 23)
- Re: S/Key & OPIE Database Vulnerability Evil Pete (Jan 24)
- Re: S/Key & OPIE Database Vulnerability Mudge (Jan 25)
- Re: S/Key & OPIE Database Vulnerability Steve VanDevender (Jan 25)
- Re: S/Key & OPIE Database Vulnerability Mudge (Jan 25)
- Stream.c needs more clarification Vanja Hrustic (Jan 25)
- Re: S/Key & OPIE Database Vulnerability Steve VanDevender (Jan 25)
- Re: S/Key & OPIE Database Vulnerability Mudge (Jan 25)
- Re: S/Key & OPIE Database Vulnerability Steve VanDevender (Jan 26)
- Future of s/key (Re: S/Key & OPIE Database Vulnerability) Frasnelli, Dan (Jan 26)
- Re: S/Key & OPIE Database Vulnerability Eivind Eklund (Jan 27)
- Re: S/Key & OPIE Database Vulnerability Jordan Ritter (Jan 27)
- Re: S/Key & OPIE Database Vulnerability Jordan Ritter (Jan 28)
- "Strip Script Tags" in FW-1 can be circumvented Arne Vidstrom (Jan 29)
- Re: S/Key & OPIE Database Vulnerability Brandon Palmer (Jan 27)
- Re: S/Key & OPIE Database Vulnerability Eivind Eklund (Jan 28)
- Multicast from hell John Watkins (Jan 27)
- Cobalt RaQ2 - a user of mine changed my admin password.. Chuck Pitre - Technical Support (Jan 27)
- Re: Cobalt RaQ2 - and QUBE2 Nir Simionovich (Rin Solo) (Jan 29)