CVE-2021-0983 in Android
Summary
by MITRE • 12/15/2021
In createAdminSupportIntent of DevicePolicyManagerService.java, there is a possible way to determine whether an app is installed, without query permissions, due to side channel information disclosure. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12Android ID: A-192245204
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-0983 resides within the Android operating system's DevicePolicyManagerService component, specifically in the createAdminSupportIntent method. This flaw represents a significant information disclosure vulnerability that allows attackers to determine the installation status of applications without requiring explicit query permissions or additional execution privileges. The issue stems from improper handling of side channel information that inadvertently reveals whether specific applications are present on the device.
The technical implementation of this vulnerability leverages timing variations and observable system behaviors that occur during the intent creation process. When the system attempts to create an administrative support intent, it processes information about installed applications in a manner that creates detectable differences in execution timing or memory access patterns. These side channel artifacts provide sufficient information to infer application installation status without direct access to package manager APIs or permission-based queries. This type of vulnerability aligns with CWE-203, Information Exposure Through Discrepancy, where system behavior reveals sensitive information through inconsistent responses or timing differences.
The operational impact of this vulnerability extends beyond simple information gathering, as it enables adversaries to perform reconnaissance activities that could facilitate subsequent attacks. An attacker could use this information to build profiles of target devices, identify potentially vulnerable applications, or determine which security tools might be present on a device. The lack of requirement for user interaction or additional privileges makes this vulnerability particularly concerning as it can be exploited automatically by malicious applications or remote attackers. This aligns with ATT&CK technique T1069.001, Permission Groups Discovery, where adversaries seek to understand the application environment and available permissions.
From a security perspective, this vulnerability demonstrates the challenges in maintaining information confidentiality when dealing with system-level services that must interact with multiple application components. The DevicePolicyManagerService operates at a privileged level within the Android security model, yet the implementation fails to properly isolate sensitive information flows. The vulnerability exists because the system does not adequately abstract or randomize the information disclosure patterns during intent processing. This represents a breakdown in the principle of least privilege and information hiding that should be maintained in security-critical system components. The Android security model relies heavily on proper encapsulation of application data, and this flaw undermines those protections by exposing application installation status through indirect means.
Mitigation strategies for this vulnerability should focus on ensuring that all information disclosure channels are properly controlled and that timing variations do not reveal sensitive information. Android developers and security teams should implement consistent processing delays or randomized timing patterns to eliminate side channel information leakage. Additionally, the DevicePolicyManagerService should be updated to ensure that all intent creation operations provide uniform behavior regardless of application installation status. System-level security hardening measures should include regular auditing of information flow patterns and implementation of proper timing randomization to prevent attackers from inferring system state through behavioral analysis. The vulnerability underscores the importance of considering side channel attacks during the security design phase of system components.