U.S. cybersecurity agency warns of ‘grave’ threat from hack

WASHINGTON » Federal authorities expressed increased alarm Thursday about an intrusion into U.S. and other computer systems around the globe that officials suspect was carried out by Russian hackers. The nation’s cybersecurity agency warned of a “grave” risk to government and private networks.

The Cybersecurity and Infrastructure Security Agency said in its most detailed comments yet that the intrusion had compromised federal agencies as well as “critical infrastructure” in a sophisticated attack that was hard to detect and will be difficult to undo.

CISA did not say which agencies or infrastructure had been breached or what information taken in an attack that it previously said appeared to have begun in March.

“This threat actor has demonstrated sophistication and complex tradecraft in these intrusions,” the agency said in its unusual alert. “CISA expects that removing the threat actor from compromised environments will be highly complex and challenging.”

The hack, if authorities can indeed prove it was carried out by a nation such as Russia as experts believe, creates a fresh foreign policy problem for President Donald Trump in his final days in office.

Trump, whose administration has been criticized for eliminating a White House cybersecurity adviser and downplaying Russian interference in the 2016 presidential election, has made no public statements about the breach.