CVE-2019-2089 in Android
Summary
by MITRE
In app uninstallation, there is a possible set of permissions that may not be removed from a shared app ID. This could lead to a local escalation of privilege with no additional execution privileges needed. User interaction is needed for exploitation. Product: Android Versions: Android-10 Android ID: A-116608833
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Analysis
by VulDB Data Team • 03/16/2020
This vulnerability exists within the Android operating system's application uninstallation process where certain permissions associated with a shared application identifier may not be properly revoked when an application is removed from the device. The flaw specifically affects Android 10 and represents a significant security concern as it enables local privilege escalation without requiring any additional execution privileges or user-level access. The vulnerability stems from improper handling of shared application IDs during the uninstallation workflow, where the system fails to completely clean up all permission grants associated with the application's shared identity.
The technical implementation of this vulnerability involves the Android permission management system's failure to properly iterate through and remove all permission grants when an application is uninstalled. When applications utilize shared user IDs, they often inherit permissions from other applications or system components that should be revoked upon uninstallation. The flaw occurs in the uninstallation routine where the system only processes direct permission assignments but overlooks inherited or shared permissions that were granted through the shared application ID mechanism. This creates a persistent permission state that allows previously uninstalled applications to maintain elevated privileges.
From an operational perspective, this vulnerability enables a malicious actor with local access to escalate privileges within the Android environment. The exploitation requires user interaction, typically through the installation of a malicious application or the manipulation of existing application states, but once triggered, the attacker can leverage the retained permissions to perform actions that should be restricted to the original application context. The impact extends beyond simple privilege escalation as it can allow access to sensitive system resources, data, and potentially enable further exploitation through the retained permission set. This vulnerability aligns with CWE-264, which addresses permissions, privileges, and access control issues in software systems.
The attack vector requires an initial foothold through user interaction, often via social engineering or application installation, but the exploitation chain leverages the Android application framework's permission handling inconsistencies. The vulnerability demonstrates a weakness in the Android security model's application lifecycle management, where the uninstallation process fails to maintain complete isolation between applications. This issue has implications for the Android security model's principle of least privilege, as applications may retain access to system resources that should be completely revoked upon removal. The vulnerability's classification under ATT&CK technique T1068, which covers local privilege escalation, further emphasizes the potential for attackers to gain elevated system access through this mechanism. Mitigation strategies should focus on ensuring complete permission cleanup during uninstallation processes and implementing additional checks to verify that all permission grants associated with shared application identifiers are properly revoked.
The vulnerability represents a critical gap in Android's application sandboxing model, where the system's failure to completely clean up shared application permissions creates a persistent security risk. This flaw particularly affects the Android security model's ability to maintain proper application isolation, as the retained permissions can provide attackers with access to system resources that should be completely inaccessible after application removal. The security implications extend to potential data exposure, unauthorized system access, and the possibility of further exploitation through the retained elevated privileges. Organizations should implement comprehensive application lifecycle management policies and ensure that system updates address this vulnerability through proper permission cleanup mechanisms during application uninstallation processes.