On Sat, 31 Mar 2007, Mikael Abrahamsson wrote:
On Sat, 31 Mar 2007, Gadi Evron wrote:
In this case, we speak of a problem with DNS, not sendmail, and not bind.
The argument can be made that you're trying to solve a windows-problem by
implementing blocking in DNS.
Next step would be to ask all access providers to block outgoing UDP/53 so
people can't use open resolvers or machines set up to act as resolvers for
certain DNS information that the botnets need, as per the same analysis that
blocking TCP/25 stops spam.
So what you're trying to do is a pure stop-gap measure that won't scale in
the long run. Fix the real problem instead of trying to bandaid the symptoms.
IMHO, Windows will always have some 0-day appearing every quarter -
whether it be in XP or Vista. Or it will be in Apache, or it will be in
Sendmail or it will be in some other app. So if taking a 10,000 foot
view, apps will always have 0-day holes that are abused. Nowadays, the
latest vector is fast-flux. I think that closing that vector via fast
closure of a particular domain name is something we should tackle. True,
the baddies will find some other vector. But that doesn't mean we should
ignore this one.
-Hank
--
Mikael Abrahamsson email: [EMAIL PROTECTED]
