Mystery malware designed to target industrial control systems has been inadvertently discovered by cybersecurity firm FireEye, the company announced on Thursday.

Those systems can include critical infrastructure like electrical grids, sewage plants, air traffic control and transportation systems. Researchers have been unable to decipher where the program they’ve dubbed “IronGate” came from, but describe it as similar in design to the “Stuxnet” virus that for years ravaged Iranian nuclear facilities.