The US government issued emergency legislation on Sunday after the largest fuel pipeline in the US was hit by a ransomware cyber-attack. The Colonial Pipeline carries 2.5 million barrels a day - 45% of the East Coast's supply of diesel, petrol and jet fuel.
Sources said the ransomware attack was likely to have been caused by a cyber-criminal gang called DarkSide, who infiltrated Colonial's network and locked the data on some computers and servers, demanding a ransom on Friday.
The cloud computing system the hackers used to collect the stolen data was taken offline on Saturday.
How did the attack occur?
The Colonial attack was helped by the coronavirus pandemic, with more engineers remotely accessing control systems for the pipeline from home. James Chappell, co-founder of Digital Shadows, said DarkSide could have bought account login details for remote desktop software such as TeamViewer and Microsoft Remote Desktop.
"We're seeing a lot of victims now, this is seriously a big problem," said Mr. Chappell. "The amount of small businesses that are falling victim to this... It's becoming a big problem for the economy globally."