Possible DNS cache poisoning attack

Kevin Darcy kcd at chrysler.com
Thu Oct 30 02:05:17 UTC 2008


Don't attribute to malice that which can be explained by stupidity.

My guess is that Facebook botched a nameserver migration, such that 
their apex NS records were pointing to unreachable nameservers. That 
would make you unable to resolve the zone until the cache was 
purged/flushed at which point you'd be able to resolve it via the 
delegation records, you'd cache the bad NS records, and the cycle would 
start all over again...

                                                                         
                                    - Kevin
Rob Tanner wrote:
> Or, at least that's what it looks like.
> Last nigh (Oct 28) we were barraged by thousands of emails with a return 
> path of facebookmail.com.  Our MTA checks the return path of each 
> incoming message so as to reject anything that can't be replied to.  
> That, of course, requires a DNS lookup but every attempt to lookup 
> facebookmail.com timed out and when I flushed the cache, it would 
> resolve for a short while and then hang again until a again flushed my 
> cache.  This effectively brought both of my email edge servers to their 
> knees as all the SMTP connections were tied up while the server was 
> waiting on DNS.
>
> I upgraded back in July when the major security bug was discovered and 
> my name servers all run BIND 9.5.0-P1.  I know there were a couple of 
> Windows specific updates since then which I ignored because I'm running 
> on Linux.  Is that version otherwise at risk and do I need to update for 
> security reasons?
>
> Thanks,
> Rob
>
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