MediaTek Chip Could Have Allowed Eavesdropping on Android

Security researchers have discovered a new flaw in a MediaTek chip used in over a third of the world's smartphones that could have potentially been used to listen in on private conversations. The chip in question is an audio processing chip by MediaTek that's found in many Android smartphones from vendors such as Xiaomi, Oppo, Realme, and Vivo. Left unpatched, researchers say, a hacker could have exploited the vulnerabilities in the chip to eavesdrop on Android users and even hide malicious code.

Check Point Research (CPR) reverse-engineered MediaTek's audio chip, discovering an opening that could allow a malicious app to install code meant to intercept audio passing through the chip and either record it locally or upload it to an attacker's server. 

CPR disclosed its findings to MediaTek and Xiaomi several weeks ago, and the four identified vulnerabilities have already been patched by MediaTek. Details on the first can be found in MediaTek's October 2021 Security Bulletin, while information on the fourth will be published in December. 

"MediaTek is known to be the most popular chip for mobile devices," Slava Makkaveev, Security Researcher at Check Point Software, said to Digital Trends in a press release. "Given its ubiquity in the world, we began to suspect that it could be used as an attack vector by potential hackers.

We embarked research into the technology, which led to the discovery of a chain of vulnerabilities that potentially could be used to reach and attack the audio processor of the chip from an Android application."

Fortunately, it looks like researchers caught the flaws before they could be exploited by malicious hackers.

Makkaveev also raised concerns about the possibility of device manufacturers exploiting this flaw "to create a massive eavesdrop campaign;" however, he notes that his firm didn't find any evidence of such misuse. 

Tiger Hsu, product security officer at MediaTek, also said that the company has no evidence that the vulnerability has been exploited but added that it worked quickly to verify the problem and make the necessary patches available to all device manufacturers who rely on MediaTek's audio processors. 

Flaws like these are also often mitigated by security features in the Android operating system and the Google Play Store, and both Makkaveev and Hsu are reminding users to keep their devices updated to the latest available security patches and only install applications from trusted locations. 

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