Application security, Incident Response, TDR

Botnet spread skyrockets in summer


The number of computers infected with botnets has quadrupled during the last three months, according to data released by volunteer watchdog Shadowserver Foundation.

Andre DiMino, a group spokesman, told that though there are more botnets, the increase might also be the result of improved monitoring abilities.

“This monitoring allows us to get a glimpse into the drones joining the party,” he said.

DiMino added that the infection factor has changed, going from email spam to websites being compromised through attacks such as SQL injection.

“The surface area is getting larger, in terms of attack vectors, which means more compromised machines and a greater number of botnets,” DiMino said.

But during the same period, there was not an appreciable increase in new malware or anything that would indicate a cause for the botnet increase.

“My thought is it has to do with SQL injections and attacks on websites,” John Bambenek, a handler with the SANS Internet Storm Center, told

The increase may also have to do with the increasing number of home computers. Tony Busa, vice president of marketing and business development at Engate Technology, an anti-botnet solutions company, said many botnets live on residential machines.

“Corporate machines have an IT staff for protection support,” he told, “but home computers don't get that support from their service providers.”

However, Busa cannot point to any specific reason why the number of hosting machines quadrupled in the summer months. He wondered if the Olympics may have been a catalyst.

“There was a lot of spam involving the Olympics, with people clicking on links that may have downloaded malware,” he said.

One thing all three experts agreed on, however, was that the trend toward more infected machines will continue.

“I think the numbers will increase into the near future,” Bambenek said, “but the anti-virus software will clamp down on it and it will start to decrease.”

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