CVE-2021-39631 in Android
Summary
by MITRE • 02/11/2022
In clear_data_dlg_text of strings.xml, there is a possible situation when "Clear storage" functionality sets up the wrong security/privacy expectations due to a misleading message. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12Android ID: A-193890833
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Analysis
by VulDB Data Team • 02/17/2022
The vulnerability identified as CVE-2021-39631 resides within the Android operating system's user interface components, specifically in the strings.xml configuration file where the clear_data_dlg_text element is defined. This flaw represents a security misconfiguration that creates a deceptive user experience during the application data clearing process. The issue manifests when users interact with the "Clear storage" functionality, which is designed to remove application data and cache files. However, the misleading message presented to users creates a false sense of security regarding what data will actually be removed, leading to potential information disclosure scenarios. The vulnerability affects Android versions 10, 11, and 12, indicating it has been present across multiple major releases of the operating system.
The technical nature of this vulnerability stems from a user interface deception pattern that falls under CWE-693 Protection Mechanism Failure, where the security mechanism fails to provide accurate information to users about the actual security implications of their actions. The flaw does not require any special privileges or additional execution capabilities for exploitation, making it particularly concerning as it can be triggered by any user with normal access to the device. The misleading message in the strings.xml file creates a gap between user expectations and the actual functionality, which represents a classic case of security by obscurity failing to provide meaningful protection. This type of vulnerability is classified as a privacy violation under the ATT&CK framework's T1566.001 technique, where social engineering through misleading UI elements is used to compromise user security.
The operational impact of CVE-2021-39631 extends beyond simple user confusion to potentially expose sensitive information that users believe has been properly cleared from their devices. When users select the "Clear storage" option expecting complete data removal, they may unknowingly retain information that could be accessed by malicious actors or applications with appropriate permissions. This situation particularly affects Android users who rely on the operating system's built-in privacy controls to protect their personal data. The vulnerability's exploitation does not require user interaction beyond the initial clearing action, meaning that malicious actors could potentially leverage this deception to gather information that users believe has been removed. This represents a significant privacy risk that could be exploited in various attack scenarios, including targeted information gathering and data exfiltration attempts.
Mitigation strategies for this vulnerability should focus on both immediate and long-term solutions. Android device manufacturers and security teams should prioritize updating the strings.xml configuration files to ensure that all user-facing messages accurately reflect the actual data clearing functionality. The fix should involve reviewing and correcting all user interface elements that relate to data clearing operations, ensuring that users receive clear and accurate information about what will be removed. Additionally, implementing more robust user interface validation mechanisms could help prevent similar issues in future releases. Security researchers and developers should also consider conducting comprehensive audits of all user-facing security messages to identify potential deception patterns. The vulnerability highlights the importance of proper security labeling and user education, as users must be accurately informed about the implications of their security actions. Organizations should also implement regular security testing procedures that specifically examine user interface elements for potential deception patterns that could compromise user privacy and security expectations.