Coast Guard and FBI boarded tankers due to cyberattacks. How big is the risk?

U.S. Coast Guard personnel and FBI agents boarded two Texas-bound energy tankers last month after cyberattacks struck the vessels while they were traveling toward the United States, according to U.S. officials.One of the vessels was the VL Prosperity, a 1,093-foot Liberian-flagged crude oil tanker headed to Galveston, Texas. Iranian state media identified the ship shortly after the incident and claimed hackers had gained access to its propulsion, navigation and cargo systems, knocking out communications for 30 hours.The Coast Guard has not publicly pinned the attacks on Iran. But Rear Adm. Amy Grable, commander of U.S. Coast Guard Cyber Command, told CBS News in a network exclusive interview that investigators did find evidence of a malicious cyber actor. "They started out by doing an assessment of the information technology and the other systems on board the vessel, and they did find malicious cyber activity," Grable said.The U.S. is investigating whether the two cyberattacks are connected and whether Iran or another foreign adversary was behind the attacks.What happened?The VL Prosperity is what's known as a supertanker — more than three football fields long and capable of carryi...