Director of National Intelligence Dan Coats has been warning the government about a 9/11-style cyberattack. Coats: All financial activity would be vulnerable, and cryptocurrencies are no safe haven. Recent attacks have illustrated the vulnerabilities of blockchain, the basis for all cryptocurrencies. Stock markets are a juicy target for hackers who continue to try to bring them down, says Coats. Security experts that protect the worlds global financial markets have defended against such attacks. But as the attacks grow more sophisticated, it will be harder and harder to defend using existing solutions.”]