FBI warns that Anonymous has hacked US government sites for a year

Activist hackers linked to the collective known as Anonymous have secretly accessed US government computers and stolen sensitive information in a campaign that began almost a year ago, the FBI warned this week.

The hackers exploited a flaw in Adobe Systems Inc’s software to launch a rash of electronic break-ins that began last December, the FBI said in a memo seen by Reuters, then left “back doors” to return to many of the machines as recently as last month.