CVE-2019-15351 in Camon
Summary
by MITRE
The Tecno Camon Android device with a build fingerprint of TECNO/H622/TECNO-ID5b:8.1.0/O11019/G-180829V31:user/release-keys contains a pre-installed platform app with a package name of com.lovelyfont.defcontainer (versionCode=7, versionName=7.0.11). This app contains an exported service named com.lovelyfont.manager.FontCoverService that allows any app co-located on the device to supply arbitrary commands via shell script to be executed as the system user that are triggered by writing an attacker-selected message to the logcat log. This app cannot be disabled by the user and the attack can be performed by a zero-permission app. Executing commands as the system user can allow a third-party app to video record the user's screen, factory reset the device, obtain the user's notifications, read the logcat logs, inject events in the Graphical User Interface (GUI), and obtains the user's text messages, and more. Executing commands as the system user can allow a third-party app to factory reset the device, obtain the user's notifications, read the logcat logs, inject events in the GUI, change the default Input Method Editor (IME) (e.g., keyboard) with one contained within the attacking app that contains keylogging functionality, and obtains the user's text messages, and more.
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Analysis
by VulDB Data Team • 02/14/2024
This vulnerability exists in Tecno Camon devices running Android 8.1.0 with build fingerprint TECNO/H622/TECNO-ID5b, where a pre-installed platform application named com.lovelyfont.defcontainer version 7.0.11 contains a critical security flaw. The application includes an exported service called com.lovelyfont.manager.FontCoverService that creates an attack surface allowing arbitrary command execution with system-level privileges. The flaw stems from improper permission controls and insecure service exposure that bypasses normal Android security boundaries. This vulnerability represents a privilege escalation issue that maps to CWE-276 and falls under the ATT&CK technique T1068 for security bypass and privilege escalation.
The technical implementation of this vulnerability exploits the fact that the FontCoverService accepts commands through shell scripts executed as the system user, triggered by writing specific messages to the logcat logging system. Attackers can leverage this mechanism without requiring any special permissions, making it particularly dangerous as it can be exploited by any application installed on the device. The service operates with elevated privileges due to its system-level installation and lack of proper access controls, allowing malicious actors to execute commands with the highest possible user privileges. This design flaw creates a persistent backdoor that cannot be disabled by users, as the application is part of the platform rather than a regular user application.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with complete system control. Third-party applications can perform screen recording to capture user activities, execute factory resets that destroy user data, access notifications containing sensitive information, read logcat logs to gather system information, inject GUI events to manipulate user interactions, and access text messages. Additionally, attackers can change the default Input Method Editor to include keylogging functionality, enabling them to capture keystrokes and passwords. These capabilities represent a comprehensive compromise of user privacy and device integrity, with the ATT&CK framework categorizing this as a complete system compromise through T1059 for command and scripting interpreter and T1070 for indicator removal.
Mitigation strategies must address both immediate and long-term security concerns. Device manufacturers should provide firmware updates that disable or remove the vulnerable service entirely, as the application cannot be uninstalled by users. Users should be advised to avoid installing untrusted applications that might exploit this vulnerability, and system administrators should monitor for unusual logcat activity that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper Android security practices including service permission controls, proper application sandboxing, and regular security audits of pre-installed applications. Organizations should implement monitoring solutions that detect unauthorized access to system services and logcat functionality to prevent exploitation of similar vulnerabilities in the future.