Oil India Limited’s computer systems were hacked in its headquarters in Dibrugarh district of Assam on April 10, PTI reported. The IT department found malware planted in the computer systems of the public sector undertaking company and shut down its network on Monday.

An first information report has been lodged at the Duliajan police station and the Cyber Cell of the Assam Police is investigating the matter

The state-run Oil India Limited’s network, server and client personal computers are facing a outage due to the cyber attack, the FIR said. The IT department had sent an email to manager Sachin Kumar on April 12 informing him of the malware, it added.

The cyber attacker has demanded $75,00,000 (Rs 57 crore) as ransom through a note found in one of the infected computers, the FIR said.

The company and government exchequer have incurred a huge loss due to the cyber attack since the IT systems have shut down operations, the complaint said.

“We have been forced to withdraw all our computer system from LAN connection after it came to our knowledge that three to four computers were hit by a virus Monday,” Oil India Limited spokesperson Tridiv Hazarika told PTI. “No computer at the headquarter now has access to internet connectivity.”

The IT department is yet to ascertain the extent of the damage, the spokesperson said.

The company is seeking help from an internationally reputed IT security consultant to restore the computers phase-wise, Hazarika told The Indian Express.

The company’s day-to-day activities have not been impacted by the cyber attack. The drilling activities are going on without interruption, the spokesperson said.