Aluminum company Norsk Hydro has already lost as much as $40.6 million since it was attacked by LockerGoga ransomware on March 19, but at least most of its operations are back running at normal capacity, the company said in a news update yesterday.

Most of the financial damage, which Hydro estimated at between 300 million to 350 million Norwegian krones ($34.8 million - $40.6 million), is the result of lost margins and volumes in the company's Extruded Solutions business area, which was the most severely impacted by the incident.

As of yesterday, Extruded Solutions was operating at 70 to 80 percent in three of its units, but its Building Systems business unit "remains almost at a standstill," the company has reported. Hydro expects this unit will gradually ramp up activity as the week proceeds.

Meanwhile, the company's Energy and Bauxite & Alumina business areas are running as normal, as are Primary Metal and Rolled Products, but with a higher degree of manual operations.

"Hydro's global IT organization is working continuously to resolve the situation together with external expertise. The company has now entered the recovery phase following the attack, gradually restoring IT systems in a safe and secure manner to ensure progress toward normal business while limiting the impact for people, operations, customers, suppliers and other partners," the news update said.

Norsk Hydro is covered by a cyber insurance policy, the company noted.