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Google has cut ties with Videostrong Technology, a China-based device manufacturer and one of its own Android partners, after more than 1.3 million of the company's Android TV boxes were found running a backdoor called XCPE. In a report published on November 2 , Google's Threat Intelligence Group says it is highly confident Videostrong built XCPE and put it on the boxes on purpose so it could make money off of them — and Google, along with a handful of security firms, took the botnet down last week.

Videostrong made that money by selling access to the infected boxes. Google says the buyers were criminal groups, and Videostrong would load their malware onto the boxes for them. A lot of that malware appears to have been built for ad fraud or for residential proxy networks — Google found as many as three residential proxy SDKs running on a single box.…