Ransomware Cyber Attack Forced the Largest U.S. Fuel Pipeline to Shut Down Colonial Pipeline, which carries 45% of the fuel consumed on the U.S. East Coast, on Saturday said it halted operations due to a ransomware attack, once again demonstrating how infrastructure is vulnerable to cyber attacks. "On May 7, the Colonial Pipeline Company learned it was the victim of a cybersecurity attack," the company said in a statement posted on its website. "We have since determined that this incident involves ransomware. In response, we proactively took certain systems offline to contain the threat, which has temporarily halted all pipeline operations, and affected some of our IT systems."