Breaching the Walls
THE 'KNEBER BOTNET'
Named after the e-mail message that launched it, this attack affected 2,411 companies and 75,000 computer systems over 18 months, according to security firm NetWitness. The source is thought to be a criminal syndicate in Eastern Europe.
GETTING INTO GOOGLE
Hackers attacked the Google e-mail accounts of Chinese human rights activists, after which the search giant threatened to leave China. The attacks were sophisticated and penetrated not just Google but 34 other companies.
In January 2009, credit-card processor Heartland Payment Systems discovered hackers had broken in. Investigators say they may have snared millions of cards. Heartland agreed a year later to pay up to $60 million to issuers of Visa credit and debit cards to resolve claims.
Data: NetWitness, Google, Heartland