A worm called "Hajime" has infected thousands of IoT devices across the globe. Security researchers do not know who created Hajime or how it might ultimately be used.
Hajime was first discovered in October 2016 and, said security researchers, had been hunting down IoT devices with security vulnerabilities that could be exploited by a different worm, called Mirai.
Earlier the same month, a network of devices compromised by Mirai was responsible for knocking offline high-profile websites including Twitter, Spotify and Reddit.
Modest estimates suggested Hajime was now present on "tens of thousands" of devices, wrote Symantec researcher Waylon Grange in a blog.