In message <5.1.1.6.2.20030628124252.033e5600@idiom.com>, Bill Stewart writes:
Somebody did an interesting attack on a cable network's customers. They cracked the cable company's DHCP server, got it to provide a "Connection-specific DNS suffic" pointing to a machine they owned, and also told it to use their DNS server. This meant that when your machine wanted to look up yahoo.com, it would look up yahoo.com.attackersdomain.com instead.
This looks like it has the ability to work around DNSSEC. Somebody trying to verify that they'd correctly reached yahoo.com would instead verify that they'd correctly reached yahoo.com.attackersdomain.com, which can provide all the signatures it needs to make this convincing.
So if you're depending on DNSSEC to secure your IPSEC connection, do make sure your DNS server doesn't have a suffix of echelon.nsa.gov...
No, that's just not true of DNSsec. DNSsec doesn't depend on the integrity of the connection to your DNS server; rather, the RRsets are digitally signed. In other words, it works a lot like certificates, with a trust chain going back to a magic root key. I'm not saying that there can't be problems with that model, but compromised DNS servers (and poisoned DNS caches) are among the major threat models it was designed to deal with. If nothing else, the existence of caching DNS servers, which are not authoritative for the information they hand out, makes a transmission-based solution pretty useless. --Steve Bellovin, http://www.research.att.com/~smb (me) http://www.wilyhacker.com (2nd edition of "Firewalls" book) --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo@metzdowd.com