1.3 million Android-based TV boxes backdoored; researchers still don’t know how

Researchers still don’t know the cause of a recently discovered malware infection affecting almost 1.3 million streaming devices running an open source version of Android in almost 200 countries.

Security firm Doctor Web reported Thursday that malware named Android.Vo1d has backdoored the Android-based boxes by putting malicious components in their system storage area, where they can be updated with additional malware at any time by command-and-control servers. Google representatives said the infected devices are running operating systems based on the Android Open Source Project, a version overseen by Google but distinct from Android TV, a proprietary version restricted to licensed device makers.

Dozens of variants

Although Doctor Web has a thorough understanding of Vo1d and the exceptional reach it has achieved, company researchers say they have yet to determine the attack vector that has led to the infections.

“At the moment, the source of the TV boxes’ backdoor infection remains unknown,” Thursday’s post stated. “One possible infection vector could be an attack by an intermediate malware that exploits operating system vulnerabilities to gain root privileges. Another possible vector could be the use of unofficial firmware versions with built-in root access.”

The following device models infected by Vo1d are:

One possible cause of the infections is that the devices are running outdated versions that are vulnerable to exploits that remotely execute malicious code on them. Versions 7.1, 10.1, and 12.1, for example, were released in 2016, 2019, and 2022, respectively. What’s more, Doctor Web said it’s not unusual for budget device manufacturers to install older OS versions in streaming boxes and make them appear more attractive by passing them off as more up-to-date models.

Further, while only licensed device makers are permitted to modify Google’s AndroidTV, any device maker is free to make changes to open source versions. That leaves open the possibility that the devices were infected in the supply chain and were already compromised by the time they were purchased by the end user.

“These off-brand devices discovered to be infected were not Play Protect certified Android devices,” Google said in a statement. “If a device isn’t Play Protect certified, Google doesn’t have a record of security and compatibility test results. Play Protect certified Android devices undergo extensive testing to ensure quality and user safety.”