CVE-2021-39693 in Android
Summary
by MITRE • 03/16/2022
In onUidStateChanged of AppOpsService.java, there is a possible way to access location without a visible indicator due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12Android ID: A-208662370
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Analysis
by VulDB Data Team • 03/20/2022
The vulnerability identified as CVE-2021-39693 resides within the Android operating system's AppOpsService.java component, specifically in the onUidStateChanged method where a logic error creates an exploitable condition for unauthorized location access. This flaw represents a significant security weakness that allows malicious applications to bypass normal location permission checks without user awareness or interaction. The vulnerability stems from improper handling of app operations and state changes that should normally trigger visibility indicators when location data is accessed, but instead permits covert access through flawed logical flow.
The technical implementation of this vulnerability involves a logic error within the AppOpsService that fails to properly validate location access permissions when a UID state changes. When an application transitions through different operational states, the system should verify that appropriate location permissions are granted and that users receive appropriate notifications about location access. However, the flawed implementation allows for location data retrieval even when normal permission checks would prevent such access, creating a pathway for privilege escalation. This logical inconsistency occurs during the uid state transition process where the system incorrectly grants location access based on incomplete or misinterpreted permission states.
From an operational perspective, this vulnerability enables local privilege escalation without requiring additional execution privileges or user interaction, making it particularly dangerous in environments where malicious applications might already have some level of access to the device. The lack of visible indicators means that users remain unaware when their location data is being accessed, creating a stealthy surveillance capability that could be exploited by malware or malicious applications. The impact extends beyond simple location tracking as it demonstrates a fundamental flaw in Android's permission system architecture that could potentially affect other sensitive operations beyond just location services. This vulnerability specifically affects Android 12 systems and represents a critical weakness in the platform's security model.
Security professionals should note that this vulnerability aligns with CWE-284 (Improper Access Control) and potentially relates to ATT&CK technique T1059 (Command and Scripting Interpreter) through potential exploitation methods. The flaw could be leveraged by attackers to establish persistent surveillance capabilities while remaining undetected by standard user interface indicators. Organizations should implement immediate mitigations including system updates, application sandboxing, and monitoring for unauthorized location access patterns. The vulnerability highlights the importance of proper state management in security-critical components and underscores the need for comprehensive permission validation mechanisms that prevent logical errors from creating security holes. This issue demonstrates how seemingly minor logic errors in core system services can create significant escalation paths that compromise user privacy and system integrity.