CVE-2019-15431 in U50A
Summary
by MITRE
The Evercoss U50A Android device with a build fingerprint of EVERCOSS/U50A./EVERCOSS:7.0/NRD90M/1499911028:eng/test-keys contains a pre-installed app with a package name of com.qiku.cleaner app (versionCode=2, versionName=2.0_VER_2017.04.21_17:55:55) that allows other pre-installed apps to perform system properties modification via an accessible app component. This capability can be accessed by any pre-installed app on the device which can obtain signatureOrSystem permissions that are required by other other pre-installed apps that exported their capabilities to other pre-installed app.
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Analysis
by VulDB Data Team • 02/20/2024
The vulnerability identified as CVE-2019-15431 represents a significant security flaw in the Evercoss U50A Android device running Android 7.0. This issue stems from a pre-installed application named com.qiku.cleaner which contains a vulnerable component that permits unauthorized modification of system properties through exported app components. The vulnerability exists within the device's permission model and component exposure mechanisms, creating a pathway for privilege escalation and system manipulation. The affected device configuration includes a specific build fingerprint that indicates a particular firmware version, making this vulnerability applicable to a defined set of devices within the Evercoss product line.
The technical flaw manifests through the improper exposure of system modification capabilities within the pre-installed cleaning application. This application exports its functionality through accessible app components that can be invoked by other pre-installed applications on the device. The vulnerability specifically leverages the Android permission model where signatureOrSystem permissions are required to access these exported capabilities. This permission level is typically reserved for system applications and those signed with the same certificate as the system, but the flaw allows other pre-installed applications to gain access through the component exposure mechanism. The vulnerability is classified under CWE-276 as improper privileges, specifically involving incorrect access control for system resources and components.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data manipulation capabilities. Any pre-installed application that can obtain signatureOrSystem permissions can leverage this vulnerability to modify critical system properties, potentially affecting device stability, security configurations, and user privacy. Attackers could exploit this to alter system settings, disable security features, or manipulate device behavior in ways that could compromise user data or device integrity. The vulnerability creates a persistent threat vector that remains active as long as the vulnerable pre-installed application exists on the device, making it particularly concerning for devices that cannot receive timely security updates.
Mitigation strategies for CVE-2019-15431 require both immediate and long-term approaches to address the underlying exposure issues. Device manufacturers should implement proper component access controls by removing or securing the vulnerable exported components within the pre-installed applications. The Android permission model should be enforced more strictly to prevent unauthorized access to system modification capabilities, potentially through the implementation of permission checks at component invocation time. Security updates should be prioritized for affected devices, with the vulnerable application either patched to remove the insecure component exposure or completely removed from the device configuration. Organizations should also consider implementing application whitelisting policies to prevent unauthorized applications from accessing system modification capabilities, aligning with ATT&CK technique T1068 for bypassing user access control measures. Additionally, regular security audits of pre-installed applications should be conducted to identify and remediate similar exposure vulnerabilities that could be exploited for system compromise.