Nov 2 (Reuters) - Occidental Petroleum Corp, the fourth-largest U.S. oil company said on Friday it faced an attack on its email system a few years ago, at a time when the energy industry emerged as a prime hacking target.
The disclosure follows a year after the U.S. Securities and Exchange Commission (SEC) issued a lengthy document detailing when publicly traded companies should report hacking incidents.
"In 2009 and 2010 Occidental experienced a cyber attack on its email system, which had no effect on its operations, financial systems or reputation," the company said in its quarterly filing with the SEC, released on Friday.
Occidental acknowledged in the new "risk factor" that cyber attacks on businesses had escalated in recent years and it relies on electronic networks to run its operations, which have "multiple layers of security to mitigate risks of cyber attack."
An Occidental spokeswoman was not immediately available for comment.
A report by leading security firm McAfee in May found that cyber espionage was on the rise, with Chinese hackers stealing field data and cutting-edge technology from energy companies around the world since at least 2009.