US officials have warned that a sophisticated hacking campaign uncovered this week poses a “grave risk” to the government, critical infrastructure and the private sector.
The US Treasury and commerce departments were among those attacked.
The US Cybersecurity and Infrastructure Security Agency (Cisa) said thwarting the attack would be “highly complex and challenging”.
Many suspect the Russian government is responsible. It has denied the claims.
In a statement on Thursday, Cisa said government agencies, critical infrastructure entities and private sector organisations had been targeted by what it called an “advanced persistent threat actor”, beginning in at least March 2020.
The actor behind the hacks “demonstrated patience, operational security, and complex tradecraft in these intrusions”, it said.
Cisa did not identify who was behind the attack; which agencies and organisations had been breached; or what information had been stolen or exposed.
Meanwhile, US President-elect Joe Biden said he would make cyber-security a “top priority” of administration.
“We need to disrupt and deter our adversaries from undertaking significant cyber-attacks in the first place,” he said. “We will do that by, among other things, imposing substantial costs on those responsible for such malicious attacks, including in coordination with our allies and partners.”
