The operator of the Colonial Pipeline learned it was in trouble at daybreak on May 7, when an employee found a ransom note from hackers on a control-room computer. By that night, the company's chief executive officer came to a difficult conclusion: He had to pay.

Joseph Blount, CEO of Colonial Pipeline Co., told The Wall Street Journal that he authorized the ransom payment of $4.4 million because executives were unsure how badly the cyberattack had breached its systems, and consequently, how long it would take to bring the pipeline back.

Mr. Blount acknowledged publicly for the first time that the company had paid the ransom, saying it was an option he felt he had to exercise, given the stakes involved in a shutdown of such critical energy infrastructure. The Colonial Pipeline provides roughly 45% of the fuel for the East Coast, according to the company.