The US Federal Bureau of Investigation had cautioned the public this week that the computers of US governments in several agencies had been hacked by a collective group of hackers known as Anonymous. The FBI also said that activist hackers tied to the group had accessed and stole sensitive information. The agency also said that the hacking by Anonymous had started around a year ago.

In a memo seen by Reuters, the FBI explained that the hackers saw a flaw in the software of Adobe Systems Inc, which resulted to a series of electronic break-ins that started last December 2012. The hackers then left many software mechanisms called "back doors" in order for them to go back to the machines in as latest as last month, the FBI said in the memo. The memo indicated that several agencies, including the U.S. Army, Department of Energy and Department of Health and Human Services had security breaches done by Anonymous.

Investigators assigned in the hacking incidents are still compiling information to determine the scope of the campaign done by Anonymous. US authorities still believed that the cyber campaign is still ongoing.

An internal email also obtained by the news agency read that stolen information were personal data of not less than 104,000 employees, contractors and even familial relations associated with the Department of Energy. The email, which came from Energy Secretary Ernest Moniz' chief of staff Kevin Knobloch, also indicated that information on around 2,000 bank accounts were also stolen.

The FBI memo wrote, "(Despite the earlier disclosures), the majority of the intrusions have not yet been made publicly known. It is unknown exactly how many systems have been compromised, but it is a widespread problem that should be addressed."

According to an article by the Wall Street Journal, cybercrime costs USD11.56 million annually on an average organization in the US. The Ponemon Institute report, which was sponsored by HP Enterprise Security Products, said this was a 78% spike from hacking costs four years ago. The study also indicated that the amount of time spent by the organizations to resolve their security breaches had jumped 130% as well. McAfee of Intel Corp, on the other hand, claimed that its study showed that average organizations spend a combined USD100 billion annually.