CVE-2021-39770 in Android
Summary
by MITRE • 03/30/2022
In Framework, there is a possible disclosure of the device owner package due to a missing permission check. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12LAndroid ID: A-193033501
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Analysis
by VulDB Data Team • 04/02/2022
The vulnerability identified as CVE-2021-39770 represents a significant information disclosure weakness within the Android framework affecting Android 12L and related versions. This flaw stems from an insufficient permission check mechanism that allows unauthorized access to sensitive device information. The vulnerability specifically targets the device owner package disclosure, which constitutes a critical privacy and security risk for Android devices. The issue resides in the framework layer where proper access controls should prevent unauthorized entities from retrieving owner package information, yet a missing permission verification creates an exploitable gap in the system's security architecture.
The technical implementation of this vulnerability exploits a fundamental flaw in Android's permission model where the framework fails to properly validate access requests for device owner package information. When an application attempts to access owner package details, the system should verify appropriate permissions before granting access. However, in this case, the permission check mechanism is either absent or improperly implemented, allowing any application with basic execution privileges to retrieve this sensitive information. This represents a direct violation of the principle of least privilege and demonstrates a failure in the Android security model's access control mechanisms. The vulnerability operates at the system level where framework components should enforce strict permission boundaries to prevent unauthorized information disclosure.
The operational impact of CVE-2021-39770 extends beyond simple information disclosure, as device owner package information can serve as a valuable asset for attackers seeking to understand the device's configuration and user environment. This type of information can be leveraged to craft more sophisticated attacks, including targeted malware that can bypass certain security measures by knowing the owner package details. The vulnerability's exploitation requires no user interaction, making it particularly dangerous as it can be triggered automatically by malicious applications without any user consent or awareness. The lack of additional execution privileges needed for exploitation means that even applications with limited permissions can potentially access sensitive owner package information, creating a wide attack surface. This vulnerability aligns with CWE-284, which addresses improper access control issues in software systems.
From a threat modeling perspective, this vulnerability creates opportunities for attackers to perform reconnaissance activities that could lead to more severe compromises. The information disclosure could enable attackers to identify device owner applications, understand the device's configuration, or even craft targeted attacks against specific applications. The vulnerability's classification under the ATT&CK framework would likely fall under the information gathering phase, specifically targeting system information discovery techniques. Security researchers have noted that such vulnerabilities often serve as precursors to more sophisticated attacks, as the disclosed information can be used to map the device's attack surface and identify potential exploitation vectors. The absence of user interaction requirements makes this vulnerability particularly concerning for mobile security, as it can be exploited silently in the background without any user awareness.
Mitigation strategies for CVE-2021-39770 should focus on implementing proper permission checks within the Android framework to prevent unauthorized access to device owner package information. System administrators and device manufacturers should ensure that all framework components properly validate access requests before granting information disclosure. The recommended approach includes strengthening the permission model to enforce stricter access controls, implementing proper access logging for suspicious activities, and ensuring that all applications undergo thorough security review before deployment. Additionally, regular security updates and patches should be applied to address the underlying framework vulnerability, as this type of issue typically requires system-level fixes rather than application-level workarounds. The vulnerability demonstrates the importance of maintaining robust security boundaries within mobile operating systems and the critical need for continuous security assessment and improvement of permission enforcement mechanisms.