More than 75,000 computer systems at nearly 2,500 companies in the United States and around the world have been hacked in what appears to be one of the largest and most sophisticated attacks by cyber criminals discovered to date, according to a northern Virginia security firm. The attack, which began in late 2008 and was discovered last month, targeted proprietary corporate data, e-mails, credit-card transaction data and login credentials at companies in the health and technology industries in 196 countries, according to Herndon-based NetWitness. News of the attack follows reports last month that the computer networks at Google and more than 30 other large financial, energy, defense, technology and media firms had been compromised. Google said the attack on its system originated in China. This latest attack does not appear to be linked to the Google intrusion, said Amit Yoran, NetWitness's chief executive. But it is significant, he said, in its scale and in its apparent demonstration that the criminal groups' sophistication in cyberattacks is approaching that of nation states such as China and Russia. Read more: Washington Post