CVE-2019-2090 in Android
Summary
by MITRE
In isPackageDeviceAdminOnAnyUser of PackageManagerService.java, there is a possible permissions bypass due to a missing permissions check. This could lead to local escalation of privilege, with no additional permissions required. User interaction is not needed for exploitation. Product: Android. Versions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9. Android ID: A-128599183
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/21/2020
The vulnerability described in CVE-2019-2090 represents a critical permissions bypass flaw within the Android package management system that enables local privilege escalation without requiring any additional user permissions. This issue exists in the PackageManagerService.java component where the isPackageDeviceAdminOnAnyUser method fails to perform proper authorization checks before allowing access to device administration privileges. The flaw resides in the Android operating system's core package management infrastructure, specifically affecting versions from Android 7.0 through Android 9.0, making it a widespread vulnerability across multiple Android releases. The vulnerability is classified under CWE-284 which addresses improper access control, specifically weak permissions checks that allow unauthorized access to protected resources. This weakness directly maps to ATT&CK technique T1068 which involves exploiting local privileges to gain elevated system access, demonstrating how attackers can leverage this flaw to bypass normal security boundaries.
The technical implementation of this vulnerability stems from the absence of proper permission verification within the PackageManagerService's device administration checking mechanism. When an application attempts to determine if a package has device admin privileges across any user context, the system fails to validate whether the calling process has the necessary authorization to perform this query. This missing authorization check creates a pathway for malicious applications to circumvent the normal device administration permission model and potentially gain elevated privileges within the system. The flaw operates at the system level where device administration permissions are typically restricted to specific privileged applications and system components, yet the missing permission validation allows any local process to query this information without proper authorization. This represents a fundamental breakdown in the Android security model's permission enforcement mechanisms.
The operational impact of CVE-2019-2090 is significant as it enables local privilege escalation without requiring user interaction or additional privileges, making it particularly dangerous for exploitation. Attackers can leverage this vulnerability to execute malicious code with elevated system privileges, potentially gaining access to sensitive system resources, modifying critical system files, or installing malicious applications with device administrator privileges. The vulnerability's exploitation does not require user interaction, which means it can be triggered automatically when applications are installed or when the system performs package management operations. This characteristic makes the vulnerability particularly attractive to attackers as it can be exploited silently in the background, potentially allowing for persistent access to compromised devices. The affected Android versions span multiple major releases, indicating that the vulnerability has been present for an extended period and has affected a substantial user base.
Mitigation strategies for CVE-2019-2090 primarily focus on applying the relevant Android security patches and updates that address the missing permission checks in the PackageManagerService. Organizations and users should immediately install the latest security updates from Google that contain fixes for this vulnerability. System administrators should ensure that all Android devices within their environment are updated to versions that include the patched PackageManagerService implementation. Additional defensive measures include implementing application whitelisting policies, monitoring for unauthorized device administration permissions, and conducting regular security audits of installed applications. The vulnerability highlights the importance of proper access control implementation in system-level components and serves as a reminder of the critical need for thorough permission validation in Android's core system services. Security professionals should also consider implementing network-based monitoring solutions that can detect anomalous behavior patterns consistent with privilege escalation attempts. Given the nature of the vulnerability, which operates at the system level without requiring user interaction, proactive patch management becomes essential for maintaining device security and preventing potential exploitation by malicious actors.