CVE-2019-2173 in Android
Summary
by MITRE
In startActivityMayWait of ActivityStarter.java, there is a possible incorrect Activity launch due to an incorrect permission check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9Android ID: A-123013720
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Analysis
by VulDB Data Team • 10/03/2020
The vulnerability identified as CVE-2019-2173 resides within the Android operating system's activity management framework, specifically in the startActivityMayWait method of the ActivityStarter.java component. This flaw represents a critical permission validation issue that affects multiple Android versions including 7.1.1, 7.1.2, 8.0, 8.1, and 9. The vulnerability stems from an incorrect permission check implementation that fails to properly validate whether an application has adequate privileges to launch certain activities. This weakness falls under the CWE-284 access control vulnerability category, specifically addressing improper access control mechanisms within the Android framework. The issue is particularly concerning as it enables local privilege escalation without requiring any additional execution privileges or user interaction, making it a significant security concern for Android devices.
The technical implementation flaw occurs when the startActivityMayWait method processes activity launch requests and performs insufficient permission validation. This method is responsible for managing activity transitions and ensuring proper security boundaries are maintained during application launches. When an application attempts to start another activity, the system should verify that the initiating application possesses the necessary permissions to perform such an operation. However, due to the flawed permission checking logic, malicious applications can bypass these security checks and launch activities that they should not have access to. The vulnerability operates at the system level within Android's core framework, specifically affecting the ActivityManager service which governs application lifecycle management and inter-application communication. This allows an attacker to potentially launch activities with elevated privileges or access restricted system components that should normally be protected from unauthorized access.
The operational impact of CVE-2019-2173 extends beyond simple unauthorized activity launches, as it creates a pathway for local privilege escalation attacks. An attacker with a malicious application installed on a vulnerable device can exploit this vulnerability to gain elevated privileges without requiring additional malicious code execution or user interaction. This means that a standard application could potentially access system-level functionality, modify protected system components, or gain access to sensitive data that should be restricted to system applications. The vulnerability is particularly dangerous because it operates silently in the background, allowing malicious code to exploit the permission flaw without alerting users or requiring them to perform any actions. From an ATT&CK perspective, this vulnerability maps to privilege escalation techniques and can be leveraged to achieve persistent access to system resources. The lack of user interaction requirement makes this vulnerability especially concerning for mobile environments where users may not be aware of the underlying security issues.
Mitigation strategies for CVE-2019-2173 primarily involve applying the official Android security patches released by Google, which address the permission validation logic in the ActivityStarter.java component. System administrators and device manufacturers should prioritize deployment of these updates across affected Android versions to remediate the vulnerability. Additionally, organizations should implement application whitelisting policies to prevent unauthorized applications from gaining access to system-level functionality. Network security measures such as mobile device management solutions can help monitor and control application behavior on affected devices. The vulnerability highlights the importance of proper access control implementation in system-level components and underscores the need for comprehensive security testing of core framework elements. Organizations should also consider implementing runtime application protection measures and regular security audits to identify similar permission-related flaws that could potentially compromise system integrity. Regular security updates and patch management processes are essential to maintaining the security posture of Android devices against such critical vulnerabilities.