CVE-2021-1032 in Android
Summary
by MITRE • 12/15/2021
In getMimeGroup of PackageManagerService.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-184745603
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Analysis
by VulDB Data Team • 12/22/2021
The vulnerability identified as CVE-2021-1032 resides within the PackageManagerService.java component of Android systems, specifically in the getMimeGroup method implementation. This flaw represents a side-channel information disclosure vulnerability that allows attackers to determine the installation status of applications without requiring explicit query permissions or user interaction. The vulnerability affects Android 12 systems and has been assigned Android ID A-184745603, highlighting its significance within the Android security ecosystem. The technical implementation of this vulnerability stems from how the system handles MIME group lookups, creating observable timing variations or other indirect information channels that can be exploited to infer application presence.
The core technical flaw manifests in the way the PackageManagerService processes MIME group queries and returns information to requesting components. When an application attempts to determine whether another application is installed through MIME group resolution, the system's response timing or error handling patterns inadvertently leak information about the target application's existence. This occurs because the getMimeGroup method does not properly normalize its response behavior across different scenarios, creating distinguishable side-channel signals that can be monitored and analyzed by an attacker. The vulnerability operates at the system level without requiring any special privileges or user interaction, making it particularly concerning for local information disclosure attacks.
The operational impact of this vulnerability extends beyond simple information gathering, as it enables attackers to perform reconnaissance activities that could facilitate more sophisticated attacks. An adversary could leverage this information to build detailed profiles of installed applications on a device, potentially identifying security-sensitive applications or those with known vulnerabilities. This capability could be combined with other attack vectors to create more effective exploitation scenarios, particularly in targeted attacks where understanding the victim's application landscape is crucial. The vulnerability's local nature means it can be exploited from within the device itself, potentially bypassing network-based security controls and detection mechanisms.
From a cybersecurity perspective, this vulnerability maps to CWE-203: "Information Exposure Through Side-Channel Timing Attacks" and aligns with ATT&CK technique T1083: "File and Directory Discovery" and T1059: "Command and Scripting Interpreter." The lack of user interaction requirements and minimal privilege needs make this vulnerability particularly dangerous as it can be exploited automatically by malicious applications already present on the device. The vulnerability demonstrates the complexity of securing modern mobile operating systems where legitimate system functions must balance performance with security considerations. Organizations should consider implementing additional monitoring for unusual timing patterns in system calls and ensure proper patching of affected Android versions to mitigate this information disclosure risk.
The remediation approach for this vulnerability involves updating to patched versions of Android 12 where the PackageManagerService has been modified to eliminate the side-channel information leakage. Security teams should monitor for any applications that might attempt to exploit this vulnerability by analyzing system call patterns and timing variations. Additionally, the vulnerability highlights the importance of proper input validation and response normalization in system services to prevent similar side-channel attacks from occurring in other components. Organizations should also consider implementing device integrity monitoring to detect anomalous behavior that might indicate exploitation attempts. The vulnerability serves as a reminder that even seemingly benign system operations can create security risks when not properly secured against side-channel analysis.