CVE-2019-20598 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with O(8.x) software. Bixby leaks the keyboard's learned words, and the clipboard contents, via the lock screen. The Samsung IDs are SVE-2018-12896, SVE-2018-12897 (May 2019).
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Analysis
by VulDB Data Team • 10/04/2020
This vulnerability affects Samsung mobile devices running Android 8.x operating system versions where the Bixby voice assistant functionality creates a security exposure through improper handling of sensitive data on the lock screen. The flaw enables unauthorized access to personal information that should remain protected when the device is secured. The vulnerability stems from the keyboard's learned word functionality and clipboard contents being accessible through the lock screen interface, creating an attack surface that violates fundamental security principles of device protection.
The technical implementation of this vulnerability involves Bixby's integration with the device's input methods and system clipboard functionality. When a user types on the lock screen, the keyboard learns words and stores them for predictive text functionality. Additionally, clipboard contents are retained in memory even when the device is locked. These elements are not properly secured or isolated from unauthorized access through the lock screen interface, allowing malicious actors or attackers with physical access to potentially extract this sensitive information. The vulnerability is particularly concerning because it operates at the system level where user privacy and data protection mechanisms should be most robust. This issue aligns with CWE-200, which addresses "Information Exposure," and represents a failure in proper access control mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks. Attackers could harvest personal vocabulary patterns, which may aid in social engineering attacks or provide insights into user behavior and preferences. Clipboard contents often contain sensitive information such as passwords, personal messages, financial data, or confidential communications that could be exploited for identity theft, financial fraud, or corporate espionage. The vulnerability is particularly dangerous because it can be exploited without requiring authentication or network connectivity, making it a significant risk for users who leave their devices unattended in public spaces or who may be targeted by opportunistic attackers.
The security implications of this vulnerability highlight the critical importance of proper input method and clipboard isolation mechanisms within mobile operating systems. Organizations and individuals should implement additional security measures beyond the device manufacturer's default protections, including enabling strong lock screen authentication, regularly updating software patches, and implementing device management policies that restrict access to sensitive features. From an att&ck framework perspective, this vulnerability maps to techniques involving credential access and information discovery, as attackers could leverage this exposure to gather intelligence about users and potentially escalate privileges. The vulnerability also underscores the need for comprehensive security testing of assistant and input system components, as these features often operate with elevated privileges and access to sensitive user data. Samsung addressed this issue through software updates that improved the isolation of keyboard learned words and clipboard functionality on locked devices, emphasizing the importance of proper access control and data protection mechanisms in mobile operating systems.