In May 2021, the Colonial Pipeline was shut down because of a ransomware attack. On first blush, it would seem as though the ransomware attack must have targeted some core systems relevant to the transmission of oil.
Well, the attack did not. The attack hit Colonial Pipeline's billing system, and then Colonial shut down its pipeline because it wasn't sure how it would bill and collect payments (see CNN link). Yup, you heard it correct. They shut down the pipeline because they were afraid they wouldn't be able to bill customers.