DDOS attack 'really, really tested' UltraDNS

A major provider of domain name system infrastructure services was hit by a distributed denial of service attack last Thursday morning described as bigger and more sophisticated than anything else it has previously seen,

writes Kevin Murphy

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UltraDNS Corp, which provides DNS services for the likes of oracle.com and top-level domains including .info and, from January 1 2003 .org, was hit by a DDoS attack unprecedented in its scale.

While no services were actually denied, the attack has got the company concerned enough to boost its bandwidth and infrastructure to prevent further attacks. UltraDNS CEO Ben Petro compared this kind of attack to "terrorism".

Petro told ComputerWire that even though the company has seen DDoS attacks before, its network was "really, really, really tested" for the first time. The attack became apparent at about 9am US Pacific Standard Time and ended three hours later.

UltraDNS has about 40 servers distributed around the globe, using BGP anycast to share the same two IP addresses. Each server saw enough traffic to fill up more than one T1 pipe during the attack's peak.

"We have not seen an attack act in this fashion with this methodology before," said Petro. He declined to discuss many precise details, but said that up to two million packets per second were flooded into its servers and that the source IP addresses were randomly spoofed.

Petro said UltraDNS, which offers a 100% service level agreement to its customers, will have "no SLA payouts" as a result of the attack. Ram Mohan, CTO of Afilias Ltd, the custodian of .info, which subcontracts its infrastructure to UltraDNS, said the company and internet users saw "no performance degradation".

The attacks came about a month after a similar attack managed to render seven of the internet's 13 DNS root servers inaccessible for an hour. At that time, experts we spoke to said crackers attempting to cause disruption to the DNS would better serve their goal by targeting a TLD server such as .com.

Now, evidently, they have. Afilias's Mohan said: "It's almost as if they're testing various TLDs to see where the weak link is." He added that it was not as big an attack as the one that hit the root servers: "I think the attack was unprecedented in its scale but I would not characterize it as massive."

"We're trying not to link these two events, but we don't see much coincidence," said Petro. He said that smaller TLDs, such as those from countries with emerging internet economies, have infrastructures "not built to prevent these near-terrorist attacks."

"We are at risk, e-commerce is at risk and to an extent the global economy is at risk," said Petro. "If you could take down .com, what would be the cost in billions of dollars?"

US Federal law enforcement agencies have been notified. The source of DDoS attacks are notoriously hard to trace. Not only do attackers use a network of dozens, hundreds or thousands of compromized "slave" machines to launch the attacks, but these slaves spoof the source IP address on floods they send.

However, UltraDNS's network uses a technology that may give an idea of roughly where most of the slaves are located. BGP anycast allows multiple servers to announce the same IP address to the internet, so users access the server closest to them. So by seeing how much traffic hit which server, it may give a general idea of where most slaves are located, once the data is compiled.

© ComputerWire