The virus, “ACAD/Medre.A”, has stolen tens of thousands of blueprints from companies mostly based in Peru, said ESET, a computer security firm.

It targeted software called AutoCAD, which is very widely used by industrial designers and architects. The stolen drawings were surreptitiously sent to email accounts provided by two Chinese internet firms, 163.com and qq.com, although this is no guarantee the criminals behind the raid were Chinese.

It is believed ACAD/Medre.A was distributed to Peruvian companies via a booby-trapped AutoCAD template that was initially sent to public bodies. The virus was first detected some months ago but ESET saw a sudden spike in infections two months ago as its authors began to exploit their creation.