DDoS Attacks Are Back and Bigger Than Before

DDoS Attacks Are Back and Bigger Than Before

Distributed denial-of-service (DDoS) attacks are certainly nothing new. Companies have suffered the scourge since the beginning of the digital age. But DDoS seems to be finding its way back into headlines in the past six months, in thanks to some high-profile targets and, experts say, two important changes in the nature of the attacks.

The targets are basically the same -- private companies and government websites. The motive is typically something like extortion or to disrupt the operations of a competing company or an unpopular government. But the ferocity and depth of the attacks have snowballed, thanks in large part to the proliferation of botnets and a shift from targeting ISP connections to aiming legitimate-looking requests at servers themselves.

In fact, said Andy Ellis, CSO of Cambridge, Mass.-based Akamai Technologies (AKAM), the botnets launching many of today's DDoS attacks are so vast that those controlling them probably lost track of how many hijacked machines they control a long time ago. (Listen to the full interview with Ellis in The Long, Strange Evolution of DDoS Attacks.)

Ellis has been watching the trend from a pretty good vantage point. Many people use Akamai services without even realizing it. The company runs a global platform with thousands of servers customers rely on to do business online. The company currently handles tens of billions of daily Web interactions for such companies as Audi, NBC, and Fujitsu, and organizations like the U.S. Department of Defense and NASDAQ. There's rarely a moment -- if at all -- when an Akamai customer IS NOT under the DDoS gun.

"We see a lot less of the fire-and-forget malware-based attacks designed to bog down the machines that were infected," Ellis said, referring to old-school worm attacks like Blaster, Mydoom and Code Red. "Now the malware is used to hijack machines for botnets and the botnets themselves are used as the weapon."

In the last year, Akamai has seen some of the largest DDoS attacks in recent memory, which Ellis described as "huge attacks of more than 120 gigabytes per second." If you are on the receiving end of that much punch, Ellis said, "It's not a pleasant place to be."

Recession hit Cyber-crime just doesn't pay like it used to.

Recession hits Cybercrime! With botnets everywhere, DDoS attacks get cheaper $30 will buy a one-day DDoS attack now!

Security researchers say the cost of criminal services such as distributed denial of service, or DDoS, attacks has dropped in recent months. The reason? Market economics. "The barriers to entry in that marketplace are so low you have people basically flooding the market," said Jose Nazario, a security researcher with Arbor Networks. "The way you differentiate yourself is on price."

Criminals have gotten better at hacking into unsuspecting computers and linking them together into so-called botnet networks, which can then be centrally controlled. Botnets are used to send spam, steal passwords, and sometimes to launch DDoS attacks, which flood victims' servers with unwanted information. Often these networks are rented out as a kind of criminal software-as-a-service to third parties, who are typically recruited in online discussion boards.

DDoS attacks have been used to censor critics, take down rivals, wipe out online competitors and even extort money from legitimate businesses. Earlier this year a highly publicised DDoS attack targeted U.S. and South Korean servers, knocking a number of Web sites offline.

Are botnet operators having to cut costs like other businesses in these troubled economic times? Security researchers don't know if that's been a factor, but they do say that the supply of infected machines has been growing. In 2008, Symantec's Internet sensors counted an average of 75,158 active bot-infected computers per day, a 31 percent jump from the previous year.

DDoS attacks may have cost hundreds or even thousands of dollars per day a few years ago, but in recent months researchers have seen them going for bargain-basement prices.

Nazario has seen DDoS attacks offered in the US$100-per-day range, but according to SecureWorks Security Researcher Kevin Stevens, prices have dropped to $30 to $50 on some Russian forums.

And DDoS attacks aren't the only thing getting cheaper. Stevens says the cost of stolen credit card numbers and other kinds of identity information has dropped too. "Prices are dropping on almost everything," he said.

While $100 per day might cover a garden-variety 100MB/second to 400MB/second attack, it might also procure something much weaker, depending on the seller. "There's a lot of crap out there where you don't really know what you're getting," said Zulfikar Ramzan, a technical director with Symantec Security Response. "Even though we are seeing some lower prices, it doesn't mean that you're going to get the same quality of goods."

In general, prices for access to botnet computers have dropped dramatically since 2007, he said. But with the influx of generic and often untrustworthy services, players at the high end can now charge more, Ramzan said.