CVE-2021-0989 in Android
Summary
by MITRE • 12/15/2021
In hasManageOngoingCallsPermission of TelecomServiceImpl.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-194105812
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-0989 resides within the TelecomServiceImpl.java component of Android operating systems, specifically affecting Android 12 implementations. This flaw represents a significant information disclosure issue that exploits a side channel attack vector to determine application installation status without requiring explicit query permissions. The vulnerability manifests through the hasManageOngoingCallsPermission method, which inadvertently exposes information about installed applications through indirect means. Security researchers have classified this issue under the broader category of information disclosure vulnerabilities, where the attacker can gather sensitive data about the device's application landscape through carefully crafted observations of system behavior.
The technical exploitation of this vulnerability occurs through a side channel information disclosure mechanism that allows malicious applications to infer whether specific applications are installed on the device. This occurs without requiring any special permissions or user interaction, making it particularly concerning from a security perspective. The flaw essentially creates a covert information channel where the presence or absence of certain applications can be determined by observing the behavior of the TelecomService implementation. This type of vulnerability falls under CWE-200, which specifically addresses "Information Exposure" and represents a form of information leakage that occurs through indirect means rather than direct data access. The implementation flaw exists in how the system handles permission checks for ongoing call management, where the response patterns to permission queries inadvertently reveal installation status information.
The operational impact of this vulnerability extends beyond simple information gathering, as it enables attackers to build detailed profiles of device users and their application ecosystems. An attacker could leverage this information to tailor more sophisticated attacks, identify potential targets for further exploitation, or conduct behavioral analysis of users. The vulnerability does not require additional execution privileges or user interaction, which significantly increases its exploitability and potential impact. This type of attack vector aligns with techniques described in the MITRE ATT&CK framework under the Information Gathering tactic, specifically targeting the collection of application and system information as a precursor to more advanced attacks. The lack of requirement for user interaction makes this vulnerability particularly dangerous as it can be exploited silently in the background without the user's knowledge or consent.
Mitigation strategies for this vulnerability should focus on implementing proper access controls and ensuring that permission checking mechanisms do not leak information through side channels. Android security teams should review the TelecomServiceImpl.java implementation to eliminate information disclosure pathways during permission validation processes. The recommended approach involves modifying the hasManageOngoingCallsPermission method to ensure that response patterns remain consistent regardless of whether target applications are installed, thereby preventing side channel attacks. Organizations should also implement comprehensive monitoring for unusual permission checking behavior and ensure that system updates are applied promptly to address this information disclosure vulnerability. The fix should align with security best practices for preventing information leakage and maintaining proper isolation between different application contexts within the Android operating system.