FBI in malware warning to US companies after cyber attack targets Sony Pictures

The Federal Bureau of Investigation has warned US businesses that hackers have used malicious software to launch a destructive cyberattack in the United States, following a devastating breach last week at Sony Pictures Entertainment.

Cybersecurity experts said the malicious software described in the alert appeared to describe the one that affected Sony, which would mark the first major destructive cyberattack waged against a company on US soil. Such attacks have been launched in Asia and the Middle East, but none have been reported in the US. The FBI report did not say how many companies had been victims of destructive attacks.

"I believe the coordinated cyberattack with destructive payloads against a corporation in the US represents a watershed event," said Tom Kellermann, chief cybersecurity officer with security software maker Trend Micro. "Geopolitics now serve as harbingers for destructive cyberattacks."

The five-page, confidential "flash" FBI warning issued to businesses late on Monday provided some technical details about the malicious software used in the attack. It provided advice on how to respond to the malware and asked businesses to contact the FBI if they identified similar malware.

The report says the malware overrides all data on hard drives of computers, including the master boot record, which prevents them from booting up.

"The overwriting of the data files will make it extremely difficult and costly, if not impossible, to recover the data using standard forensic methods," the report said.