CVE-2019-2103 in Assistant
Summary
by MITRE
In Google Assistant in Android 9, there is a possible permissions bypass that allows the Assistant to take a screenshot of apps with FLAG_SECURE. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-2103 represents a significant permissions bypass flaw within Google Assistant's implementation on Android 9 devices. This issue stems from the Assistant's ability to circumvent the FLAG_SECURE protection mechanism that applications employ to prevent screenshots of sensitive content. The FLAG_SECURE flag is a standard Android security feature designed to protect applications from being captured through screen recording or screenshot functionality, particularly in contexts where sensitive data might be displayed. When an application sets this flag, it explicitly instructs the Android system to prevent any screen capture operations from occurring, thereby protecting confidential information such as passwords, personal data, or financial details from being inadvertently exposed through screenshots.
The technical exploitation of this vulnerability occurs through the Google Assistant's screenshot functionality, which appears to ignore or bypass the FLAG_SECURE restrictions that should normally prevent such operations. This flaw essentially allows the Assistant to capture screenshots of applications that have explicitly disabled screenshot capabilities, creating a pathway for information disclosure that should have been prevented by the application's security configuration. The vulnerability is particularly concerning because it requires no user interaction for exploitation, meaning that an attacker could potentially leverage this flaw automatically without requiring any deliberate action from the user. This autonomous exploitation capability significantly increases the risk profile of the vulnerability, as it can be triggered silently in the background without any visible user prompts or consent.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally undermines the security model that applications rely upon to protect sensitive data. When applications set FLAG_SECURE, they are making a security assertion that their content should remain protected from screen capture operations, which is a critical security control for applications handling sensitive information. The bypass of this protection mechanism means that any application that depends on FLAG_SECURE for security can have its contents captured and potentially exposed. This vulnerability affects the integrity of Android's permission and security model, as it demonstrates that a system-level assistant application can override application-level security controls that are designed to protect user data. The implications are particularly severe for applications in banking, healthcare, or other sensitive domains where users expect their data to remain protected from unauthorized screen capture operations.
This vulnerability aligns with CWE-284, which addresses improper access control issues in software systems, and can be mapped to ATT&CK technique T1056.001 for Input Capture, specifically focusing on the capture of screen content that should remain protected. The flaw represents a critical breakdown in Android's security architecture where system-level applications can override application-level security controls without proper authorization. Organizations and users should be particularly concerned about this vulnerability because it affects the fundamental security assumptions that applications make when implementing FLAG_SECURE. The lack of user interaction requirement makes this vulnerability particularly dangerous in automated attack scenarios where malicious actors could potentially exploit it without detection. Security practitioners should consider this vulnerability as a critical component of their Android security assessment, particularly for environments where sensitive data processing occurs. The vulnerability also highlights the importance of proper privilege separation in Android system components and the need for more robust enforcement of application security controls by system-level services.