A hacking group believed to have links to the Chinese government penetrated the Metropolitan Transportation Authority's computer systems in April 2021, exposing vulnerabilities in a vast transportation network that carries millions of people every day. Hackers compromised 3 of the transit authority's 18 computer systems. The response to the intrusion cost the agency an estimated $370,000.

https://www.nytimes.com/2021/06/02/nyregion/mta-cyber-attack.html