The complex spying malware arrived via a USB stick to the work computer of the unit head in the Department for European Policy, where it was picked up by virus scanning software, according to Monday's edition of the German newspaper Bild.

According to the report, the staff member, who works in close contact with German Chancellor Angela Merkel, had written a draft of a speech on her work computer, which she then took home using a USB stick at the end of the day and worked on it using her private laptop.

She later saved the document again on her private USB stick and brought it back into the office, to use on her work laptop. A virus alert went off and it was detected that the USB stick was infected with the spying software Regin. Checks of all other high-security laptops in the Federal Chancellery revealed no additional infections.

The cybersecurity company Symantec first warned of the highly-sophisticated malware at the end of November. According to them, the Regin spying software can make screenshots, control the mouse cursor, steal passwords, monitor data traffic and restore deleted data.

According to US news website "The Intercept," which was co-created by Edward Snowden confidant Glenn Greenwald, Regin was deployed to steal information from governments, companies and research institutions. According to them, the British spy agency GCHQ and the United States spy agency NSA were involved in the development of the sophisticated spying software, which is particularly difficult to detect.

se/rg (AFP, dpa)