CVE-2021-0735 in Android
Summary
by MITRE • 08/11/2022
In PackageManager, there is a possible way to get information about installed packages ignoring limitations introduced in Android 11 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-13Android ID: A-188913056
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Analysis
by VulDB Data Team • 09/10/2022
The vulnerability identified as CVE-2021-0735 resides within the PackageManager component of Android operating systems, specifically affecting versions up to Android 13. This flaw represents a significant security weakness that undermines the permission model designed to protect user privacy and system integrity. The vulnerability stems from a missing permission check within the PackageManager service, which is responsible for managing application installations, updates, and package information on Android devices. This oversight creates an exploitable pathway that allows unauthorized access to package information that should otherwise be restricted.
The technical nature of this vulnerability lies in the absence of proper authorization validation within the PackageManager's internal mechanisms. When applications attempt to query package information, the system should verify that the requesting component has appropriate permissions to access such data. However, in this case, the permission checking mechanism fails to properly validate access requests, enabling malicious actors to bypass intended restrictions. This missing validation occurs at a fundamental level within the Android security architecture, specifically in the package management service that handles package-related queries and information retrieval operations.
The operational impact of CVE-2021-0735 is substantial as it enables local information disclosure without requiring any additional privileges or user interaction. Attackers can exploit this vulnerability to gather sensitive information about installed applications on a device, potentially including package names, versions, and other metadata that could be used for further exploitation. The vulnerability's classification as a local information disclosure aligns with CWE-200, which addresses the exposure of sensitive information to unauthorized actors. This weakness particularly affects Android 11 and earlier versions where additional restrictions were implemented to limit package information access, but the missing permission check effectively circumvents these protections.
From a threat modeling perspective, this vulnerability can be categorized under the ATT&CK framework as T1069.001 - Permission Groups, where adversaries can leverage missing permission checks to gain unauthorized access to system information. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited automatically without requiring any form of social engineering or user deception. The exploitation process involves leveraging the missing permission check within the PackageManager service to query package information that should be restricted to authorized components only.
The mitigation strategies for CVE-2021-0735 primarily focus on implementing proper permission validation within the PackageManager service. Android security updates typically address such issues by adding the missing permission checks and ensuring that all package information queries are properly authenticated. Organizations should ensure that devices running affected Android versions receive timely security patches. The vulnerability highlights the critical importance of comprehensive permission validation in system services and demonstrates how a single missing check can compromise the entire security model. Regular security audits of system components should include verification of permission enforcement mechanisms to prevent similar issues from emerging in future releases.