Wisconsin Cyber Threat Response Alliance

The scale of a sophisticated cyberattack on the U.S. government that was unearthed this week is much bigger than first anticipated. 

The Cybersecurity and Infrastructure Security Agency said in a summary Thursday that the threat “poses a grave risk to the federal government.”

It added that “state, local, tribal, and territorial governments as well as critical infrastructure entities and other private sector organizations” are also at risk.

CISA believes the attack began at least as early as March. Since then, multiple government agencies have reportedly been targeted by the hackers, with confirmation from the Energy and Commerce departments so far.

“This threat actor has demonstrated sophistication and complex tradecraft in these intrusions,” CISA said. “Removing the threat actor from compromised environments will be highly complex and challenging.”

(Reuters) -Suspected Russian hackers who broke into U.S. government agencies also spied on less high-profile organizations, including groups in Britain, a U.S. internet provider and a county government in Arizona, according to web records and a security source.

More details were revealed on Friday of the cyber espionage campaign that has computer network security teams worldwide scrambling to limit the damage as a senior official in the outgoing administration of U.S. President Donald Trump explicitly acknowledged Russia’s role in the hack for the first time.