CVE-2021-0472 in Android
Summary
by MITRE • 06/11/2021
In shouldLockKeyguard of LockTaskController.java, there is a possible way to exit App Pinning without a PIN due to a permissions bypass. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11 Android-9 Android-10Android ID: A-176801033
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Analysis
by VulDB Data Team • 06/18/2021
The vulnerability identified as CVE-2021-0472 resides within the Android operating system's LockTaskController.java component, specifically in the shouldLockKeyguard method implementation. This flaw represents a critical permissions bypass that undermines the security controls designed to maintain app pinning functionality. The vulnerability affects multiple Android versions including Android 9, 10, and 11, indicating a widespread impact across the Android ecosystem. The issue stems from improper access control mechanisms that fail to adequately validate user permissions when determining whether keyguard locking should be enforced during app pinning operations.
The technical exploitation of this vulnerability occurs through a privilege escalation vector that allows unauthorized processes to bypass the required PIN authentication mechanism. When an application is pinned in lock task mode, the system should enforce strict security controls including PIN verification before allowing any exit from the pinned application state. However, the flaw in the shouldLockKeyguard method permits bypassing these security checks without requiring additional execution privileges or user interaction. This represents a fundamental breakdown in the Android security model's enforcement of app pinning restrictions, creating a pathway for malicious actors to gain unauthorized access to the device's interface and potentially sensitive data.
The operational impact of this vulnerability extends beyond simple bypass of security controls to represent a significant threat to device security and user privacy. An attacker exploiting this vulnerability could gain access to all device features and applications that are typically restricted when app pinning is active. This includes the ability to navigate away from pinned applications, access the home screen, and potentially interact with other applications or system services that should remain protected. The lack of requirement for user interaction makes this vulnerability particularly dangerous as it can be exploited automatically without any user awareness or consent, aligning with attack patterns classified under the MITRE ATT&CK framework's privilege escalation techniques.
From a compliance perspective, this vulnerability directly impacts the security posture of Android devices and violates fundamental security principles outlined in CWE-284, which addresses improper access control mechanisms. The vulnerability demonstrates a failure in implementing proper authorization checks that should prevent unauthorized access to restricted system functionality. Organizations relying on Android devices for enterprise or government use cases face significant risks as this vulnerability could be leveraged to compromise sensitive information or escalate privileges to gain full device control. The security implications extend to potential data leakage, unauthorized device access, and the undermining of trust in Android's lock task and app pinning security features.
The recommended mitigations for this vulnerability include immediate deployment of security patches provided by Google as part of their regular Android security updates. Device administrators should ensure all Android devices are updated to the latest security patch levels, particularly those versions that contain fixes for the LockTaskController.java component. Additionally, organizations should implement additional monitoring and access control measures to detect unauthorized device behavior that might indicate exploitation attempts. Network administrators should consider implementing device management policies that restrict the use of vulnerable Android versions in enterprise environments until proper security updates are applied. The vulnerability highlights the importance of maintaining up-to-date security controls and demonstrates the critical need for continuous vulnerability assessment and patch management processes in mobile device security programs.