CVE-2020-0397 in Android
Summary
by MITRE
In getNotificationBuilder of CarrierServiceStateTracker.java, there is a possible permission bypass due to an unsafe PendingIntent. This could lead to local information disclosure with User execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-8.1 Android-9 Android-10 Android-11 Android-8.0Android ID: A-155092443
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Analysis
by VulDB Data Team • 09/18/2020
The vulnerability identified as CVE-2020-0397 resides within the CarrierServiceStateTracker.java component of Android operating systems spanning versions 8.0 through 11. This issue manifests in the getNotificationBuilder method where an unsafe PendingIntent implementation creates a potential permission bypass scenario. The flaw operates at the intersection of Android's notification system and permission model, specifically targeting how notifications are constructed and executed within the carrier service context. The vulnerability's classification as a permission bypass aligns with CWE-284, which addresses improper access control mechanisms in software systems. This weakness enables malicious actors to potentially access sensitive information through unauthorized notification handling.
The technical implementation of this vulnerability involves the creation of a PendingIntent object that does not properly validate or restrict the permissions associated with the notification builder. When the system constructs notifications for carrier service state changes, it creates a PendingIntent that could be manipulated by malicious applications to execute code with elevated privileges. The unsafe PendingIntent construction allows for information disclosure through notification mechanisms that should otherwise be restricted to authorized components. This issue specifically affects the Android notification subsystem's ability to properly enforce permission boundaries, creating a pathway for unauthorized information access.
From an operational perspective, this vulnerability requires only user execution privileges to exploit, meaning that a malicious application running with standard user permissions could potentially access sensitive information through the notification system. The lack of user interaction requirement for exploitation makes this vulnerability particularly concerning as it can be triggered automatically without any explicit user consent or awareness. The impact extends across multiple Android versions, indicating a widespread issue within the platform's notification handling architecture that affects users of various Android releases including the major versions 8.1, 9, 10, and 11. This vulnerability directly relates to the ATT&CK technique T1056.001 which covers input injection through notification manipulation.
The security implications of CVE-2020-0397 represent a significant concern for Android device security, as it allows for local information disclosure through notification system manipulation. This vulnerability could potentially expose sensitive carrier information, network state details, or other confidential data that should remain protected within the system's permission boundaries. The flaw demonstrates how notification system components can inadvertently create security loopholes that bypass normal access controls. Security professionals should consider this vulnerability as part of broader Android security assessments, particularly focusing on notification handling and PendingIntent validation mechanisms. The vulnerability's persistence across multiple Android versions suggests that organizations need to implement comprehensive patch management strategies to ensure all affected devices receive appropriate security updates.
Mitigation strategies for this vulnerability should focus on proper PendingIntent implementation that enforces strict permission validation and avoids creating unsafe notification handlers. Android developers and security teams should ensure that notification builders properly validate the permissions associated with PendingIntent objects and implement appropriate access controls. The fix typically involves modifying the getNotificationBuilder method to use proper PendingIntent flags and validation mechanisms that prevent unauthorized execution paths. Organizations should also consider implementing additional monitoring for suspicious notification handling patterns and ensure that all Android devices receive timely security updates. This vulnerability serves as a reminder of the importance of proper permission handling in notification systems and the potential for seemingly benign components to create significant security risks.