Halliburton determined it was hit by a cyberattack Wednesday after an unauthorized third party gained access to some of its systems, the company said Friday in a regulatory filing. 

Halliburton has launched an investigation after an unauthorized actor gained access to some of its systems in a hacking incident discovered Wednesday, according to 8-K filing with the Securities and Exchange Commission.  

The Houston-based company, one of the world’s leading energy services providers, said it proactively shut off certain systems and notified law enforcement after learning of the intrusion.  

Halliburton is working with outside advisors to investigate the incident, restore its internal systems and determine any material business impact.  

The company said it is communicating with customers and other stakeholders. 

Halliburton is one of the largest diversified energy services companies in the world, with more than 48,000 employees and annual revenue of $23 billion.