Cutwail botnet 'recovers quickly'

The Cutwail botnet, which was recently dealt a blow when Californian ISP Pricewert was shut down, recovered in a matter of hours.

According to the MessageLabs Intelligence report for June 2009, the botnet, which was generating thousands of spam emails, was back to one-third of its original size soon after the shutdown of Pricewert.

Pricewert was shut down after the Federal Trade Commission (FTC) ruled that it had knowingly enabled illegal activities involving spam email and child abuse websites.

The company protested the order and initially vowed to take the FTC to court.

"Cutwail’s recovery to one-third of its original levels, after only a few hours, highlights the progress spammers have made since the McColo shutdown in November," said Paul Wood, MessageLabs Intelligence senior analyst at Symantec.

"Spammers have learned the importance of having a back-up for command and control channels," he continued.

Botnets accounted for 83.2 per cent of all spam email sent in June, the report found.