CVE-2021-1014 in Android
Summary
by MITRE • 12/15/2021
In getNetworkTypeForSubscriber 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-186776740
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Analysis
by VulDB Data Team • 12/18/2021
This vulnerability resides in the Android system's telephony subsystem, specifically within the PhoneInterfaceManager.java component that handles network type queries for subscriber information. The flaw represents a side channel information disclosure issue that allows malicious applications to indirectly determine the presence of other applications on the device without requiring explicit permission to query installed packages. The vulnerability stems from how the system exposes network type information through the getNetworkTypeForSubscriber method, creating an information leak that can be exploited to infer application installation status through timing variations or other observable behavioral differences.
The technical implementation of this vulnerability leverages the Android framework's handling of telephony interface management where network type queries are processed. When an application makes network type requests, the underlying system behavior differs based on whether certain applications are present in the device's package list. This differential behavior creates a timing or response pattern that can be monitored and analyzed to deduce installed application information. The vulnerability affects Android 12 systems and is catalogued under Android ID A-186776740, demonstrating how low-level system interfaces can inadvertently expose sensitive information through indirect channels.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a potential attack vector for adversaries seeking to enumerate applications on target devices. Attackers can exploit this weakness to build profiles of installed applications without requiring the dangerous REQUEST_PACKAGE_USAGE_STATS permission or similar elevated privileges. This capability enables more sophisticated attacks where threat actors can tailor their exploitation strategies based on the applications present on a device, potentially leading to targeted malware deployment or further privilege escalation attempts. The vulnerability is particularly concerning because it requires no user interaction for exploitation and can be triggered through normal telephony operations.
Security professionals should implement mitigations focusing on restricting information flow through telephony interfaces and ensuring that system responses remain consistent regardless of application installation status. The vulnerability aligns with CWE-200 (Information Exposure) and can be mapped to ATT&CK technique T1518 (Software Discovery) in the adversary tactics framework. Organizations should ensure their Android devices are updated to versions that address this specific information disclosure channel, while also implementing network monitoring to detect unusual telephony interface usage patterns that might indicate exploitation attempts. Additionally, developers should review their applications' telephony interface usage and consider implementing additional input validation and response normalization to prevent similar side channel vulnerabilities in custom implementations.