According to a series of news accounts today, it looks like twitter was either hacked or not hacked, depending on who you listen to. The bottom line seems to be that Twitter’s DNS servers were hijacked. How this was done has not been revealed. Twitter seems to be dodging the brunt of the blame because their provider runs their DNS servers. (Confirmed by a quick nslookup below). While this may be true, that only reflects how twitter should react internally. The risk to twitter’s users is still the same. If the hackers had wanted to do damage instead of showing off by putting up a “look at me I’m so cool” type of page, then they would have forwarded users to a phishing page that intercepted authentication credentials. (While this has fairly trivial implications for twitter, imagine if they did this for a bank).

C:\>nslookup

> set type=ns
> twitter.com
Server:  UnKnown
Address:  x.x.x.x

(root)
primary name server = trafficdns1.ddc.com
responsible mail addr = hostmaster.jettissystems.com
serial  = 2009072301
refresh = 43200 (12 hours)
retry   = 3600 (1 hour)
expire  = 1209600 (14 days)
default TTL = 3600 (1 hour)

Update: more details on the DNS records can be found at SANS’ incident handler diary.