CVE-2016-6769 in Android
Summary
by MITRE
An elevation of privilege vulnerability in Smart Lock could enable a local malicious user to access Smart Lock settings without a PIN. This issue is rated as Moderate because it first requires physical access to an unlocked device where Smart Lock was the last settings pane accessed by the user. Product: Android. Versions: 5.0.2, 5.1.1, 6.0, 6.0.1. Android ID: A-29055171.
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Analysis
by VulDB Data Team • 07/20/2020
The vulnerability identified as CVE-2016-6769 represents a significant security flaw in Android's Smart Lock feature that could potentially allow unauthorized access to device security settings. This issue affects Android versions 5.0.2, 5.1.1, 6.0, and 6.0.1, specifically targeting the Smart Lock implementation that manages device unlock mechanisms. The vulnerability operates under the weakness category of privilege escalation, where a local attacker with physical access to an unlocked device could exploit this flaw to bypass normal authentication requirements.
The technical nature of this vulnerability stems from improper access controls within the Smart Lock settings interface. When a user accesses Smart Lock settings and then locks the device, the system should enforce proper authentication requirements before allowing access to these security-sensitive configurations. However, the flaw allows a malicious local user to circumvent this protection mechanism, enabling access to Smart Lock settings without requiring the proper PIN or authentication credentials. This issue falls under the CWE-284 weakness category, which deals with improper access control, specifically targeting the security boundaries that should protect sensitive system configurations.
The operational impact of this vulnerability is significant despite requiring physical access to an unlocked device. The Moderate severity rating reflects the prerequisite conditions necessary for exploitation, yet the potential consequences remain concerning for device security. An attacker with physical access to an unlocked device could manipulate Smart Lock settings to disable security features, modify trusted locations or devices, or otherwise compromise the device's security posture. This vulnerability directly impacts the integrity and confidentiality of user data, as it could enable unauthorized modification of security policies that protect the device from unauthorized access.
The attack vector for this vulnerability requires a local user with physical access to an unlocked device where Smart Lock was the last accessed settings pane. This constraint means that the attacker cannot exploit this vulnerability remotely or through network-based attacks. The attack must occur during an active session where the device is unlocked, making it a local privilege escalation issue rather than a remote code execution vulnerability. According to ATT&CK framework, this scenario maps to privilege escalation techniques that leverage local system weaknesses to gain elevated access rights, specifically targeting the Android system's permission model and security boundary enforcement mechanisms.
Mitigation strategies for this vulnerability should focus on proper access control implementation and security boundary enforcement. Android security updates should enforce strict authentication requirements for accessing sensitive settings, regardless of the last accessed interface. System administrators and device manufacturers should ensure that all Android devices receive timely security patches that address this access control weakness. Users should be advised to maintain physical security of their devices and to regularly update their systems to protect against known vulnerabilities. The recommended approach includes implementing proper session management controls and ensuring that sensitive system configurations require explicit authentication even when accessed through seemingly benign interfaces. This vulnerability underscores the importance of comprehensive security testing for all system interfaces, particularly those that manage critical security features like device unlock mechanisms and authentication policies.