Criminal hackers doing the bidding of the Russian government are believed to have hacked into a non-classified White House computer network last year, according to a person with knowledge of the investigation.
An analysis of the malicious code and other evidence gathered show certain characteristics known to be used by criminal hackers working under the sponsorship of the Russian government, said the person who wasn’t authorized to speak publicly about the investigation.
The White House intrusion, which some U.S. officials believe was carried out by hackers who had earlier gained entry into State Department computers, was likely a signal from the government in Moscow in retaliation for sanctions the U.S. has imposed on Russia, the person said.
The White House said in October that it had identified potentially threatening activity on its computer network and tried to close off access. At the time, two U.S. officials who sought anonymity said cybersecurity specialists suspected that the intrusion was carried out by either the Russian government or criminal hackers.
The hackers may have gained access to White House data through an earlier intrusion at the State Department, where officials regularly use e-mail to communicate with colleagues, according to U.S. officials who spoke on condition of anonymity.
“As we made clear at the time, we took immediate measures to evaluate and mitigate the activity,” Mark Stroh, a National Security Council spokesman, said in an e-mail.
The Russian embassy in Washington didn’t immediately respond to a phone call seeking comment.
Earlier, Russia rejected a report by CNN Tuesday that its government was involved in hacking a non-classified White House computer network that exposed sensitive parts of the e-mail system.
“It has become a kind of sport to blame everything on Russia,” Kremlin spokesman Dmitry Peskov told reporters on a conference call on Wednesday. “But the key thing is that they wouldn’t go searching for Russian submarines in the Potomac River, like it was the case in some other countries.”
Deputy White House National Security Adviser Ben Rhodes said Tuesday on CNN that no classified information had been compromised, while declining to link any attacks to Russia.
U.S. intelligence officials say the pace and sophistication of Russian-sponsored attacks have increased as tension over Ukraine has grown and the U.S. has imposed economic sanctions on Russia.