CVE-2021-0987 in Android
Summary
by MITRE • 12/15/2021
In getNeighboringCellInfo of PhoneInterfaceManager.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-190619791
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-0987 resides within the Android operating system's PhoneInterfaceManager.java component, specifically in the getNeighboringCellInfo method. This flaw represents a significant information disclosure issue that exploits a side channel attack vector to determine application installation status without requiring explicit permission queries. The vulnerability exists in Android 12 and affects the underlying telecommunications framework that manages cellular network information. Security researchers have classified this as a local information disclosure vulnerability that can be exploited without user interaction, making it particularly concerning for mobile security.
The technical root cause of this vulnerability stems from the improper handling of cellular network information within the telephony interface manager. When applications attempt to access neighboring cell information through the getNeighboringCellInfo method, the system inadvertently exposes information about installed applications through timing variations or other observable side channel characteristics. This occurs because the telephony subsystem does not adequately sanitize its responses when processing requests for cellular network data, creating observable differences in behavior that can be leveraged by malicious applications. The flaw operates at the system level within the Android framework, making it accessible to any application with basic telephony permissions.
From an operational impact perspective, this vulnerability enables attackers to perform application reconnaissance without requiring explicit permission grants or user consent. An adversary can determine whether specific applications are installed on a device by monitoring the responses from the getNeighboringCellInfo method, potentially enabling more sophisticated attacks such as targeted malware deployment or social engineering campaigns. The vulnerability's exploitation requires no additional execution privileges beyond what is normally granted to applications, making it accessible to any app that can make telephony calls or access cellular network information. This capability represents a serious privacy concern as it allows for passive monitoring of application landscapes on target devices, potentially revealing sensitive information about user behavior and installed software.
The security implications extend beyond simple application discovery to encompass broader privacy and security threats within the Android ecosystem. This vulnerability aligns with CWE-200 (Information Exposure) and represents a variant of side channel attacks that exploit timing differences or behavioral variations in system responses. From an ATT&CK framework perspective, this vulnerability maps to T1592 (Gather Victim Host Information) and T1593 (Gather Victim Network Information) techniques, as it enables adversaries to collect information about installed applications and network connectivity characteristics. The vulnerability demonstrates how seemingly benign system interfaces can be exploited to create covert information channels that bypass traditional permission models and security boundaries.
Mitigation strategies for this vulnerability should focus on implementing proper input sanitization and response normalization within the telephony interface manager. Android security patches should ensure that the getNeighboringCellInfo method does not expose information about application installation status through side channel mechanisms. System-level protections should include response time normalization and consistent handling of network information requests regardless of application state. Organizations should also consider implementing application sandboxing and runtime monitoring to detect anomalous behavior patterns that might indicate exploitation attempts. Regular security updates and proper permission management practices remain essential in defending against such information disclosure vulnerabilities that can undermine user privacy and system security.