Evan Schuman's StorefrontBacktalk

Distributed denial-of-service attacks on commercial Web sites have taken a nasty turn since last year: They’re now throwing four times as many packets, and the type of packets are more likely to bring targeted sites to their knees. That’s according to security vendor Prolexic Technologies, which on Thursday (Nov. 17) is slated to release a report that says since Q3 2010, attackers have shifted from attacks that aim at Web servers to those that target routers—a change that could require retailers to put up much stronger defenses against brute-force attacks.

It’s hard enough defending against a botnet firing an endless stream of “show me your homepage” requests at an E-Commerce site. Retailers have already seen those attacks amped up to 50 times their previous level during a few days after Black Friday last year. But the new style of attack (so far aimed mainly at online gambling sites) is likely to require a lot more hardware to pick off nasty packets—and it’s hardware that’s only necessary until the attack ends, at which point it’s very expensive bric-a-brac.

According to the Prolexic report, the new attacks have shifted from the network’s application layer (for example, using packets containing the HTTP GET command) to the transport and Internet layers (using lower-level network traffic signals). In network jargon, that means the new-style attacks are mostly SYN floods, ICMP floods and UCP floods—all arriving at a rate of millions of packets per second, and all of which have to be dealt with one packet at a time.

“The bad news is, you can’t just ACL that off,” said Neal Quinn, VP of operations at Prolexic. “You have to let traffic through, and you need a DDoS mitigation appliance to authenticate the SYN requests. That’s north of $150,000.” Unfortunately, those appliances still aren’t designed to handle the level of attack bandwidth that this year’s attacks are using. “You really need a provider who has a huge deployment of those appliances to spread the load out globally,” Quinn said.

Not surprisingly, that’s the business Prolexic is in. But hiring out the attack-mitigation work to some provider makes painful financial sense. According to the report, a typical attack lasts about a day and a half. A million dollars’ worth of in-house hardware that might actually be used at most a few days out of each year? Sure, that’ll go over big with your CFO.

And unfortunately, it’s the attackers who get to pick the game.