Haliburton, a massive oil field company, was recently forced to take its systems down after unknown hackers launched a devastating cyberattack. Some oil pipelines were also affected.

In a recent 8-K report sent to the Securities and Exchange Commission (SEC), Haliburton reported that a hacker obtained access to its systems, but details are sparse. The attack is still largely a mystery. As of now, no threat actors have taken responsibility for the attack and there is no specific method of attack that’s been disclosed to the public.

Due to Haliburton’s position as a goliath oil company, there’s no telling which hacker group it could have been.

“We are aware of an issue affecting certain company systems and are working diligently to assess the cause and potential impact.” Haliburton’s spokesperson explained after the attack. “We have activated our preplanned response plan and are working internally, and with leading external experts, to remediate the issue.”

The 8-K includes Halubrton’s response plans.

“The Company’s response efforts included proactively taking certain systems offline to help protect them and notifying law enforcement. The Company’s ongoing investigation and response include restoration of its systems and assessment of materiality,” Halburton’s Vice President writes.

Over the past several years, hackers have ramped up their attacks on oil pipelines. This includes large oil fields like Shell and the Colonial Pipeline as well as smaller oil rigs around the world. Haliburton is another victim in a long line.

The attacks on oil fields haven’t gone unnoticed. Since the attack on the Colonial Pipeline, government organizations around the world have implemented strict cybersecurity regulations for their oil rigs.

In June, G7 leaders declared that they would strengthen the cybersecurity of the global supply chain and oil. However, many of these changes haven’t been implemented yet. The company is currently investigating the attack alongside independent contractors.