The operations are difficult to stop due to their international nature, the speed with which cybercriminals react to shutdowns and the lack of law enforcement resources or interest.

McColo's shutdown came after research was which showed the extent to which the company was involved in the criminal underground.

Similarly, another noted bad ISP -- known as Atrivo or Intercage -- was cut off by its upstream providers in September as a result of mounting pressure from the computer security community.

"With the recent cases of McColo and Atrivo/Intercage taken off the Internet, it will be easier in the future to put more pressure on other known hosters of badware to take action or go offline," said Toralv Dirro, security strategist for McAfee's Avert Labs, on Thurday.