#Android #Rootkit – Powerful backdoor/rootkit found preinstalled on 3 million Android phones : Almost three million Android phones, many of them used by people in the US, are vulnerable to code-execution attacks that remotely seize full control of the devices, researchers said Thursday.

Until recently, the flaw could have been exploited by anyone who took the time to obtain two Internet domains that remained unregistered despite being hardwired into the firmware that introduced the vulnerability. After discovering the vulnerability, researchers from security ratings firm BitSight Technologies registered the addresses and control them to this day. Even now, the failure of the buggy firmware to encrypt communications sent to a server located in China makes code-execution attacks possible when phones don’t use virtual private networking software when connecting to public hotspots and other unsecured networks.

Since BitSight and its subsidiary company Anubis Networks took possession of the two preconfigured domains, more than 2.8 million devices have attempted to connect in search of software that can be executed with unfettered “root” privileges, the researchers said. Had malicious parties obtained the addresses before BitSight did, the actors could have installed keyloggers, bugging software, and other malware that completely bypassed security protections built into the Android operating system. The almost three million devices remain vulnerable to so-called man-in-the-middle attacks because the firmware—which was developed by a Chinese company called Ragentek Group—doesn’t encrypt the communications sent and received to phones and doesn’t rely on code-signing to authenticate legitimate apps. Based on the IP addresses of the connecting devices, vulnerable phones hail from locations all over the world, with the US being the No. 1 affected country.

“The thing that scares us is a lot of these users will be unaware of the vulnerability, and they will never get an update,” BitSight CTO Stephen Boyer told Ars. “This is full system compromise. This is at the root level. [Attackers with a MitM position] can do anything.”

Kind of BLU

In a blog post published Thursday, BitSight researchers said they went to a Best Buy store and purchased a BLU Studio G phone and were able to perform an attack that exploited the backdoor. As a result, they were able to install a file they named system_rw_test in /data/system/, a file location that’s reserved for apps with all-powerful system privileges. The researchers provided the following screenshot:

BitSight Technologies

By observing the data phones sent when connecting to the two previously unregistered domains, BitSight researchers have cataloged 55 known device models that are affected. The most affected manufacturer is US-based BLU Products, which accounted for about 26 percent, followed by multinational Infinix with 11 percent, Doogee with almost 8 percent, and Leagoo and Xolo with about 4 percent each. Slightly more than 47 percent of the phones that connected to the BitSight sinkhole gave no indication who their manufacturer was. A list of specific models can be found in this advisory from the Department of Homeland Security-sponsored CERT.

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