A ransomware group is threatening to leak data stolen from Taiwan-based printed circuit board (PCB) manufacturer Unimicron Technology.

Unimicron is one of the world’s largest PCB makers, with manufacturing sites in China, Germany and Japan. 

The company announced on February 1 that its IT systems had been targeted in a ransomware attack on January 30. 

Unimicron said at the time that it had launched an investigation aided by an external cyber forensics team, but it expected impact on the company’s operations to be limited.

The Sarcoma ransomware group listed Unimicron on its Tor-based leak website on February 11 and the cybercriminals are threatening to make the stolen data public in less than a week unless a ransom is paid. 

In an effort to demonstrate their claims, the hackers have released screenshots of several documents allegedly stolen from Unimicron systems. They claim to be in possession of 377 Gb of files (archived). 

The Sarcoma group’s website currently lists roughly 70 victims targeted since October 2024. The hackers use a double extortion strategy — encrypting files on compromised systems and stealing valuable data to pressure the victim to pay up. 

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