The attack is known as DNS Amplification. It has been used sporadically since December, but it started getting talked about last month when ISPrime, a small New York Internet service provider, started getting hit hard with what's known as a distributed denial of service (DDOS) attack. The attack was launched by the operator of a pornographic Web site who was trying to shut down a competitor, hosted on ISPrime's network, according to Phil Rosenthal, the company's chief technology officer.

The attack on ISPrime started on the morning of Sunday, Jan. 18. It lasted about a day, but what was remarkable was that a relatively small number of PCs were able to generate a very large amount of traffic on the network.

One day later, a similar attack followed, lasting three days. Before ISPrime was able to filter the unwanted traffic, attackers were able to use up about 5GB/second of the company's bandwidth,

With a bit of work, Rosenthal's staff was able to filter out the hostile traffic, but in an e-mail interview he said that the attack "represents a disturbing trend in the sophistication of denial of service attacks."

According to Don Jackson, director of threat intelligence at security vendor SecureWorks, we may soon see a lot more of these DNS Amplification attacks. Late last week, the botnet operators, who rent out their networks of hacked computers to the highest bidder, started adding custom DNS Amplification tools to their networks.