A dangerous backdoor has been discovered in the MediaTek processor that could be exploited to hack Android devices remotely. The vulnerability is apparently due to a debug tool that was opened up for carriers to test the device on their networks, but unfortunately, it was left open in the shipped devices. If exploited, the debug feature could allow hackers to compromise personal data of an Android device, including user’s private contacts, messages, photos, videos and other private data. It was mainly found in devices running Android 4.4 KitKat.
Source: https://thehackernews.com/2016/02/mediatek-hacking-mobile.html