CVE-2016-3889 in Android
Summary
by MITRE
Android 6.x before 2016-09-01 and 7.0 before 2016-09-01 allows physically proximate attackers to bypass the Factory Reset Protection protection mechanism by accessing (1) an external tile from a system application, (2) the help feature, or (3) the Settings application during a pre-setup stage, aka internal bug 29194585.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability described in CVE-2016-3889 represents a critical security flaw in Android operating systems affecting versions 6.x and 7.0 released prior to September 1, 2016. This weakness specifically targets the Factory Reset Protection mechanism, which is designed to prevent unauthorized access to devices after a factory reset operation. The vulnerability allows attackers who are physically present near an Android device to circumvent this crucial security feature, effectively undermining the device's primary protection against theft and unauthorized use. The flaw exists in the pre-setup stage of device configuration, when users are prompted to set up their devices for the first time or after a factory reset has been performed.
The technical implementation of this vulnerability stems from insufficient access controls and authentication checks within the Android system's setup process. Attackers can exploit three distinct entry points to bypass the Factory Reset Protection mechanism: accessing external tiles from system applications, utilizing the help feature, or navigating through the Settings application during the pre-setup phase. These access points provide unauthorized users with opportunities to manipulate the device setup process before the security protections are fully established. The vulnerability is particularly concerning because it operates at a fundamental level within the Android operating system's security architecture, allowing attackers to gain access to device functionality that should remain restricted until proper authentication occurs.
The operational impact of this vulnerability extends beyond simple unauthorized device access, as it enables attackers to potentially extract sensitive data, install malicious applications, or perform other unauthorized actions on the device. The fact that this vulnerability can be exploited by physically proximate attackers means that it does not require network connectivity or sophisticated attack vectors, making it particularly dangerous in real-world scenarios. Security researchers have categorized this vulnerability under CWE-284, which describes improper access control issues, and it aligns with ATT&CK technique T1211, which covers external remote access tools. The vulnerability essentially creates a backdoor into the device setup process that can be exploited to undermine the device's security posture from the very beginning of its operational lifecycle.
Mitigation strategies for CVE-2016-3889 primarily involve applying the security patches released by Google as part of their monthly security updates. Organizations and individuals should ensure their Android devices are updated to versions released after September 1, 2016, which contain fixes for this vulnerability. The recommended approach includes implementing comprehensive device management policies that enforce regular security updates and monitoring for unauthorized access attempts. System administrators should also consider deploying additional security controls such as device encryption, secure boot mechanisms, and network-based access controls to provide defense-in-depth protection. The vulnerability demonstrates the critical importance of timely security patch management and highlights how seemingly minor access control flaws can have significant implications for device security and user privacy.