WASHINGTON (AFP/REUTERS/BLOOMBERG) - United States officials insisted on Tuesday that a cyber attack late last year did not compromise White House classified systems, but refused to confirm reports that Russia was behind the breach.
White House deputy national security adviser Ben Rhodes said in an appearance on CNN on Tuesday that the White House in 2014 disclosed cyber intrusions that did not affect classified information. "We have an unclassified system and then we have a classified system, a top secret system," Mr Rhodes said. "We do not believe that our classified systems were compromised."
"There was an event last year," said Mr Rhodes. "We have classified systems that are secure. We don't talk about where cyber intrusions originate from."
CNN reported on Tuesday that Russia was behind the October attack that originated at the State Department, but was confirmed to have hit the White House too. It said Russian hackers penetrated sensitive parts of the White House computer system after intruding at the State Department in recent months, citing US officials briefed on the matter.
The White House said the report did not refer to a new incident, but was "speculating" about the source of cyber activities that were disclosed last year. National Security Council spokesman Mark Stroh Spokesman Mark Stroh said in a statement that the White House would not comment on CNN's attribution of the cyber attack to Russian hackers and said the report was "speculating" on who was behind an attack that affected the unclassified "Executive Office of the President" network.
The Executive Office is made up of President Barack Obama's closest advisers, including the National Security Council and Council of Economic Advisors, as well as the Vice-President's staff.
While separate from classified systems, that network is used to exchange sensitive information about White House activities, such as detailed breakdowns of the president's movements.
"Any such activity is something we take very seriously," Mr Stroh said. "We took immediate measures to evaluate and mitigate the activity."
Federal Bureau of Investigation spokesman Paul Bresson declined to comment on Tuesday.
CNN said the hackers had gained access to unclassified but potentially sensitive information such as non-public details of the President's schedule.
The White House said in October that it had identified potentially threatening activity on its computer network and had taken immediate steps to address it. At the time, two US officials who sought anonymity said cybersecurity specialists suspected that Russian government or criminal hackers were responsible for the intrusion.
Some US officials investigating the intrusion suspect that the hackers may have gotten into unclassified White House systems after gaining entry at the State Department, where officials regularly use e-mail to communicate with colleagues, according to US officials who spoke on condition of anonymity.
The State Department incident late last year proved difficult to root out, the officials said, because the hackers kept revising their tools to foil defensive efforts.
Mr Obama recently ordered a new sanctions programme that could block assets of US and foreign hackers and of companies that seek to profit from cyber attacks.
Mr Obama said the threat from cyber attacks was a "national emergency".
"Starting today, we're giving notice to those who pose significant threats to our security or economy," he said.
China, Russia and Iran are seen as most active in the cyber warfare arena.
US intelligence officials say the pace and sophistication of Russian-sponsored attacks have increased as tension over Ukraine has grown and the US has imposed economic sanctions on Russia.