CVE-2021-39619 in Android
Summary
by MITRE • 02/11/2022
In updatePackageMappingsData of UsageStatsService.java, there is a possible way to bypass security and privacy settings of app usage due to an unusual root cause. 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-12Android ID: A-197399948
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Analysis
by VulDB Data Team • 02/17/2022
The vulnerability identified as CVE-2021-39619 resides within the Android operating system's usage statistics service implementation, specifically in the updatePackageMappingsData method of UsageStatsService.java. This flaw represents a critical security weakness that undermines the privacy and security controls designed to protect user application usage data. The issue manifests as an improper access control mechanism that allows unauthorized processes to bypass established security boundaries governing usage statistics collection and access. The vulnerability affects Android versions 11 and 12, making it particularly concerning given the widespread deployment of these operating system versions across mobile devices worldwide. The Android ID A-197399948 further categorizes this issue within the platform's security tracking system, indicating its severity and the need for immediate attention from device manufacturers and security teams.
The technical root cause of this vulnerability stems from a flaw in how the UsageStatsService handles package mapping data updates, creating an unexpected pathway for privilege escalation. When the updatePackageMappingsData method processes incoming package information, it fails to properly validate or enforce access controls that should normally prevent unauthorized modifications to usage statistics mappings. This anomalous behavior allows malicious applications or processes to manipulate the system's understanding of which applications have access to usage data, effectively bypassing the security mechanisms that normally protect user privacy. The vulnerability operates at a low level within the Android framework where usage statistics are managed, making it particularly dangerous as it can be exploited without requiring any special user interaction or additional execution privileges beyond what the system already provides. This characteristic places the vulnerability squarely within the category of local privilege escalation issues that can be exploited by applications already running on the device.
The operational impact of CVE-2021-39619 extends beyond simple data access violations, as it enables a complete bypass of the Android privacy controls that govern application usage statistics. Attackers who successfully exploit this vulnerability can gain unauthorized access to comprehensive usage data including which applications are running, how long they are active, and potentially even behavioral patterns that could reveal sensitive information about user activities. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited silently in the background without any warning to the user. This type of flaw directly violates the principle of least privilege and can potentially lead to more severe consequences including the ability to track user behavior across applications, monitor sensitive activities, and gather intelligence that could be used for targeted attacks or data exfiltration. The vulnerability's classification aligns with CWE-284 (Improper Access Control) and can be mapped to ATT&CK technique T1059 (Command and Scripting Interpreter) when exploited by malicious applications that leverage the privilege escalation to execute further malicious activities.
Mitigation strategies for this vulnerability require immediate action from Android device manufacturers and system administrators. The most effective approach involves applying the security patches provided by Google through the Android Security Bulletins, which address the specific access control flaw in the UsageStatsService implementation. Organizations should also implement monitoring solutions that can detect anomalous usage statistics access patterns that might indicate exploitation attempts. Device users should ensure their Android systems are updated to the latest security patches, particularly those released in the Q3 2021 Android Security Updates. Additionally, security teams should review application permissions and usage statistics access controls within their environments, as the vulnerability could potentially be leveraged to bypass existing security measures that rely on proper access control enforcement. The vulnerability demonstrates the importance of robust access control validation within core system services and highlights the need for continuous security auditing of Android framework components that handle sensitive user data.