Colonial Pipeline has resumed operations of its main pipeline after a ransomware attack forced a five-day closure of the line carrying 45% of the East Coast’s diesel, petrol and jet fuel supply.

It will take “several days for the product delivery supply chain to return to normal”, Colonial said in a statement published Wednesday.

The operator of the biggest US fuel pipeline took its IT systems offline on Friday after they were infected with file-encrypting malware. It began the restart of pipeline operations on Wednesday at around 5pm ET.

Colonial said on Tuesday that it had delivered approximately 41 million gallons of fuel via alternative methods while the pipeline system has been offline. The US government used emergency measures to relax rules on fuel being transported by road to help prevent interruptions in supplies.

The 5,500-mile-long pipeline is one of the largest in the US, typically carrying 2.5 million barrels of fuel a day along the East Coast. Colonial restored operations at some of its smaller lines on Monday.

The FBI confirmed that ransomware rented out by the DarkSide cybercrime group was responsible for the shutdown. In a statement posted Monday DarkSide appeared to point the blame at one of its affiliates. Colonial said it will not pay the ransom demand.

DarkSide is a ransomware-as-service group that rents out its software and infrastructure to other cybercriminals, taking a cut of their earnings. Its ransomware does not target systems where the language is set to Russian and it avoids attacking former Soviet states. Russia has denied any involvement in the attack. The White House has stated that it didn’t suspect the Kremlin of backing the hack.

The shutdown caused petrol prices to jump to $3.008 per gallon on average, breaking the $3 mark for the first time since the end of 2014, according to AAA. Panic at the gas pumps caused the US Consumer Product Safety Commission to tweet: “Do not fill plastic bags with gasoline.”

Colonial Pipeline

The lines operated by Colonial Pipeline. (via Colonial Pipeline)

Virginia and Georgia are among the states hardest hit by gas shortages.

“Some markets served by Colonial Pipeline may experience, or continue to experience, intermittent service interruptions during the start-up period,” Colonial said in its latest update on Wednesday. “Colonial will move as much gasoline, diesel and jet fuel as is safely possible and will continue to do so until markets return to normal.”

Colonial Pipeline’s website remains inaccessible. In a Twitter update on Tuesday the pipeline operator said this outage is “unrelated to the ransomware.”

Executive order makes MFA mandatory

In response to attacks against the US government and critical infrastructure, including the Colonial Pipeline, Exchange Server and SolarWinds hacks, Biden yesterday issued an executive order aimed at improving supply chain security.

It requires all federal civilian branch agencies to adopt multifactor authentication (MFA), as well as encryption for data at rest and in transit by default.

The move has been welcomed by security professionals, including the Fast IDentity Online (FIDO) Alliance, an open industry association promoting authentication standards.

“If there is one thing the attack on SolarWinds as well as the Colonial Pipeline ransomware attack reminded us, the private sector and public sector need strong security measures to protect critical infrastructure – and the FIDO Alliance believes this begins with authentication,” said Andrew Shikiar, FIDO Alliance executive director and CMO. “We urge government agencies to adopt only the strongest forms of MFA when complying with this directive.”