Compromised environments will be highly complex and challenging

 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.

Mr. Trump, whose administration has been criticised for eliminating a White House cybersecurity advisor and downplaying Russian interference in the 2016 Presidential election, has made no public statements about the breach. President-elect Joe Biden said he would make computer engineer salary a top priority of his administration, but that stronger defences are not enough.

We need to disrupt and deter our adversaries from undertaking significant cyberattacks 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.