WASHINGTON – Russian President Vladimir Putin’s track record of unleashing destructive “hybrid warfare” cyberattacks has U.S. security officials fearing he could once again reach across continents and wreak havoc on unwitting Americans as worries about a possible Russian invasion of Ukraine persist.
They call it the “spillover effect.” And they say the temporary takedown of some prominent Ukrainian military and financial sector websites Tuesday resembled the kind of prelude to more significant Russian cyberwarfare attacks that could get out of hand.

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