The number of command-and-control (C&C) servers sending commands to Koobface-infected computers doubled in a recent 48-hour period, according to Kaspersky Lab. On Monday, the number of C&C servers was at 71, down from 107 on Feb. 25, but quickly rose to 142 by Wednesday. Stefan Tanase, Kaspersky's senior anti-virus researcher, said the gang behind Koobface is "prepared with dozens of new servers" when too many are shut down. The Koobface worm typically spreads through social networking sites, such as Facebook and Twitter, and there have been hundreds of variants since it first appeared in 2008. — DK