CVE-2016-3908 in Android
Summary
by MITRE
The Lock Settings Service in Android 6.x before 2016-10-01 and 7.0 before 2016-10-01 allows attackers to remove a device s PIN or password, and consequently gain privileges, via a crafted application, aka internal bug 30003944.
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Analysis
by VulDB Data Team • 05/01/2019
The vulnerability identified as CVE-2016-3908 represents a critical security flaw in the Lock Settings Service component of Android operating systems. This vulnerability affected Android 6.x versions prior to the 2016-10-01 security update and Android 7.0 before its corresponding patch release. The issue stems from insufficient authorization checks within the system's lock settings management functionality, creating a pathway for malicious applications to manipulate device security configurations without proper user consent or administrative privileges. The vulnerability is particularly concerning because it directly impacts the fundamental security model of mobile devices, allowing attackers to bypass critical authentication mechanisms.
The technical implementation of this vulnerability exploits a weakness in the Android system's permission model and inter-process communication mechanisms. Specifically, the Lock Settings Service fails to properly validate the identity and privileges of applications attempting to modify device lock settings. An attacker can craft a malicious application that leverages this flaw to programmatically remove PIN or password protections from the device. This occurs through improper validation of the calling application's credentials and lack of sufficient sandboxing between system services and user applications. The vulnerability operates at the system level rather than through user interaction, making it particularly stealthy and dangerous as it can be exploited without user awareness or consent.
The operational impact of CVE-2016-3908 extends far beyond simple privilege escalation. Once exploited, the vulnerability allows attackers to gain full access to a device that was previously protected by PIN or password authentication. This creates a complete compromise of the device's security posture, potentially exposing sensitive user data, enabling further attacks through the compromised device, and allowing for persistent access to corporate networks if the device is used for business purposes. The vulnerability aligns with CWE-284, which addresses improper access control issues, and can be mapped to ATT&CK technique T1548.002 for bypassing user account control mechanisms. The flaw essentially undermines the core principle of device security by allowing unauthorized modification of authentication settings through legitimate system interfaces.
Mitigation strategies for this vulnerability require immediate patch deployment across all affected Android versions, with particular emphasis on the October 2016 security updates released by Google. Organizations should implement comprehensive mobile device management policies that enforce timely security updates and monitor for potentially malicious applications that might attempt to exploit this vulnerability. System administrators should also consider implementing additional security controls such as device encryption, remote wipe capabilities, and network access controls to limit the potential damage from successful exploitation. The vulnerability demonstrates the importance of proper access control implementation in system services and highlights the need for robust permission models that prevent unauthorized modification of critical security settings. Additionally, users should be educated about the risks of installing applications from untrusted sources and the importance of keeping their devices updated with the latest security patches.