Apro-Kremlin group has already taken responsibility. State-sponsored hacking activity is hard to defend against, especially very sophisticated ones. The White House has being warning of this for a while.

Doing nothing is not a good answer. As we previously discussed, companies should steps now to defend against state-sponsored attackers and be prepared for these sophisticated attacks.

The European Parliament website on Wednesday faced a "sophisticated" cyberattack disrupting its services moments after members voted to declare Russia a state sponsor of terrorism.
"I confirm that the Parliament has been subject to an external cyber attack, but the Parliamentary services are doing well to defend the Parliament," Dita Charanzová, Czech MEP and Parliament vice president responsible for cybersecurity, said in a statement.
Another senior Parliament official, requesting not to be named, said "it might be the most sophisticated attack that the Parliament has known so far."

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