The hack that took down the largest fuel pipeline in the U.S. and led to shortages across the East Coast was the result of a single compromised password, according to a cybersecurity consultant who responded to the attack.
Hackers gained entry into the networks of Colonial Pipeline Co. on April 29 through a virtual private network account, which allowed employees to remotely access the company’s computer network, said Charles Carmakal, senior vice president at cybersecurity firm Mandiant, part of FireEye Inc., in an interview. The account was no longer in use at the time of the attack but could still be used to access Colonial’s network, he said.
The account’s password has since been discovered inside a batch of leaked passwords on the dark web. That means a Colonial employee may have used the same password on another account that was previously hacked, he said. However, Carmakal said he isn’t certain that’s how hackers obtained the password, and he said investigators may never know for certain how the credential was obtained.
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Storage tanks at a Colonial Pipeline Inc. facility in Avenel, New JerseyPhotographer: Mark Kauzlarich/Bloomberg
The VPN account, which has since been deactivated, didn’t use multifactor authentication, a basic cybersecurity tool, allowing the hackers to breach Colonial’s network using just a compromised username and password. It’s not known how the hackers obtained the correct username or if they were able to determine it on their own.
“We did a pretty exhaustive search of the environment to try and determine how they actually got those credentials,” Carmakal said. “We don’t see any evidence of phishing for the employee whose credentials were used. We have not seen any other evidence of attacker activity before April 29.”