The CVE-2019-2114 bug resided in the fact that the Android Beam app was also whitelisted, receiving the same level of trust as the official Play Store app. Google said this wasn’t meant to happen, as the Android Beam service was never meant as a way to install applications, but merely as a way to transfer data from device to device. The October 2019 Android patches removed the Android Beam service from the OS whitelist of trusted sources. However, many millions of users remain at risk. If users have the NFC service and the Android Beam service enabled, a nearby attacker could plant malware (malicious apps) on their phones.Since most newly-sold devices have the NFC feature enabled by default, you’ll have to disable Android Beam and NFC or update your phone to receive the October 2019 security updates if you want to protect yourself from this bug.
An anonymous reader quotes a report from ZDNet: Google patched last month an Android bug that can let hackers spread malware to a nearby phone via a little-known Android OS feature called NFC beaming. NFC beaming works via an internal Android OS service known as Android Beam. This service allows an Android device to send data such as images, files, videos, or even apps, to another nearby device using NFC (Near-Field Communication) radio waves, as an alternative to WiFi or Bluetooth. Typically, apps (APK files) sent via NFC beaming are stored on disk and a notification is shown on screen. The notification asks the device owner if he wants to allow the NFC service to install an app from an unknown source. But, in January this year, a security researcher named Y. Shafranovich discovered that apps sent via NFC beaming on Android 8 (Oreo) or later versions would not show this prompt. Instead, the notification would allow the user to install the app with one tap, without any security warning.