SAN FRANCISCO - Authorities have smashed one of the world's biggest networks of virus-infected computers, a data vacuum that stole credit cards and online banking credentials from as many as 12.7 million poisoned PCs. The "botnet" of infected computers included PCs inside more than half of the Fortune 1,000 companies and more than 40 major banks, according to investigators. Spanish investigators, working with private computer-security firms, have arrested the three alleged ringleaders of the so-called Mariposa botnet, which appeared in December 2008 and grew into one of the biggest weapons of cybercrime. More arrests are expected soon in other countries. Spanish authorities have planned a news conference for Wednesday in Madrid. The arrests are significant because the masterminds behind the biggest botnets aren't often taken down.

- Associated Press