CVE-2020-0399 in Android
Summary
by MITRE
In showLimitedSimFunctionWarningNotification of NotificationMgr.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-8.0 Android-8.1 Android-9 Android-10 Android-11Android ID: A-153993591
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Analysis
by VulDB Data Team • 09/18/2020
The vulnerability identified as CVE-2020-0399 resides within the Android notification management system, specifically in the NotificationMgr.java component where the showLimitedSimFunctionWarningNotification method processes pending intents. This flaw represents a critical permission bypass vulnerability that allows malicious applications to potentially access sensitive user information through improper intent handling mechanisms. The issue affects multiple Android versions including 8.0, 8.1, 9, 10, and 11, indicating a widespread impact across the Android ecosystem. The vulnerability is classified under CWE-284 which specifically addresses improper access control, making it a fundamental security flaw in the Android permission model. The exploit requires only user execution privileges, meaning a malicious application already running on the device can leverage this vulnerability without requiring additional user interaction or elevated privileges.
The technical root cause stems from the unsafe handling of PendingIntent objects within the notification system. When the showLimitedSimFunctionWarningNotification method creates or processes pending intents, it fails to properly validate or secure the intent parameters, creating an opportunity for privilege escalation. This unsafe PendingIntent construction allows attacker-controlled applications to manipulate the intent flags and target components, potentially enabling information disclosure through unauthorized access to system resources. The vulnerability operates at the system level where notification management services interact with underlying Android security frameworks, making it particularly dangerous as it can be exploited to access sensitive data that should normally be restricted to system processes or specific authorized applications.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally undermines the Android security model's ability to enforce proper access controls. An attacker with user-level privileges can potentially access SIM-related information, device identifiers, or other sensitive data that should remain protected within the system's security boundaries. This type of vulnerability aligns with ATT&CK technique T1068 which describes 'Exploitation for Privilege Escalation' and T1074 which covers 'Data Staged" - the ability to access and potentially exfiltrate sensitive information. The local nature of the exploit means that it can be leveraged without network connectivity, making it particularly concerning for devices that may be compromised through other attack vectors or through physical access.
Mitigation strategies for this vulnerability should focus on implementing proper PendingIntent security practices and ensuring that all pending intent creation follows secure coding guidelines. Android developers and security teams should enforce the use of FLAG_IMMUTABLE for pending intents where possible, and implement proper validation of intent parameters before processing. The patch for this vulnerability would typically involve modifying the NotificationMgr.java implementation to properly secure pending intent creation and prevent unauthorized access to system resources. Organizations should prioritize updating affected Android versions and implementing security monitoring to detect potential exploitation attempts. Additionally, the vulnerability highlights the importance of regular security audits of system-level components and proper adherence to secure coding practices as outlined in the OWASP Mobile Top 10 and Android Security Best Practices guidelines.