It has not taken long for Joe Biden to get an answer to the warning he gave Vladimir Putin at their June 16 summit about Russian cyberattacks. “Are they going to act?” he asked rhetorically after they met on the shores of Lake Geneva.

“We’ll find out … ”. After the latest and biggest ransomware attack so far by Russian hackers, reportedly linked to the SVR, Mr. Putin’s Foreign Intelligence Service, the US President has his answer. He has warned Mr. Putin Washington is prepared to take “any necessary action” to halt the attacks.

The five-day attack halted JBS’s operations around the world, including in Australia and Canada. REvil struck again last week, attacking 1500 companies in the US, Europe, and Asia in what is reportedly the largest single “salvo” in history.

The FBI and the National Security Agency believe the same Russian outfit was behind the Solar Winds attack on strategic US government agencies and corporations in December, including the US Energy Department, which controls the National Nuclear Security Agency.

The attacks show Mr. Putin has paid little attention to Mr. Biden’s demand to stop the cybercriminals, many of which operate in collaboration with official Russian agencies. Others, Western intelligence officials believe, operate in accordance with what they believe to be official Kremlin wishes, ensuring they will not be targeted by law enforcement bodies.

With so much at stake for the US and its allies, Mr. Biden must fulfill his promise to end the Russian cyber onslaught. The Five Eyes intelligence group could be a useful vehicle to limit the attacks.