U.S. government agencies and private companies rushed Monday to secure their computer networks following the disclosure of a sophisticated and long-running cyber-espionage intrusion suspected of being carried out by Russian hackers.
The full extent of the damage is not yet clear. But the potential threat was significant enough that the Department of Homeland Security's cybersecurity unit directed all federal agencies to remove compromised network management software and thousands of companies were expected to do the same.
What was striking about the operation was its potential scope as well as the manner in which the perpetrators managed to pierce cyber defenses and gain access to email and internal files at the Treasury and Commerce departments and potentially elsewhere.
The intrusion was stark evidence of the vulnerability of even supposedly secure government networks, even after well-known previous attacks.
"It's a reminder that offense is easier than defense and we still have a lot of work to do," said Suzanne Spaulding, a former U.S. cybersecurity official who is now a senior adviser at the Center for Strategic and International Studies.
The identity of the perpetrator remained unclear. A U.S. official, speaking on condition of anonymity because of an ongoing investigation, told The Associated Press on Monday that Russian hackers are suspected.
The Washington Post, citing unnamed sources, said the attack was carried out by Russian government hackers who go by the nicknames APT29 or Cozy Bear and are part of that nation's foreign intelligence service.
The intrusion came to light after a prominent cybersecurity firm, FireEye, learned it had been breached and alerted that foreign governments and major corporations were also compromised. The company did not say who it suspected, though many experts believed Russia was responsible given the level of skill involved.
U.S. authorities acknowledged that federal agencies were affected by the breach on Sunday, providing few details. The Cybersecurity and Infrastructure Security Agency, known as CISA, said in an unusual directive that the widely used network software SolarWinds had been compromised and should be removed from any system using it.
SolarWinds is used by hundreds of thousands of organizations around the world, including most Fortune 500 companies and multiple U.S. federal agencies. The perpetrators were able to embed malware in a security update issued by the company, based in Austin, Texas. Once inside, they could impersonate system administrators and have total access to the infected networks, experts said.
"Quite honestly, my heart sank when I saw some of the details, just the amount of information they could potentially have if they are reading everyone's emails and they are accessing sensitive files within places like Treasury or Commerce," said Ben Johnson, a former National Security Agency cyber-engineer who is now chief technology officer of software security firm Obsidian.
National Security Council spokesman John Ullyot said Monday that the Trump administration was working with CISA, U.S. intelligence agencies, the FBI and government departments affected by the intrusion to coordinate a response.
"It's obviously incredibly significant and widespread," said Chris Painter, who coordinated cyber-policy at the State Department during the Obama administration. "How much was compromised? How much was exfiltrated? There are lots of open questions now."
Kremlin spokesman Dmitry Peskov said Monday that Russia had "nothing to do with" the hack.
Cybersecurity experts said the nature and level of tradecraft involved in this latest effort suggest a foreign nation. Many have pointed out that the goal of the months-long effort appeared to be espionage and not information that could be quickly used for profit or to simply inflict damage. Russia was the most likely culprit, though China and perhaps others are potential candidates.