CVE-2021-1026 in Android
Summary
by MITRE • 12/15/2021
In startRanging of RttServiceImpl.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-194798757
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Analysis
by VulDB Data Team • 12/22/2021
This vulnerability resides in the Android operating system's Bluetooth Low Energy ranging functionality within the RttServiceImpl.java component. The flaw manifests in the startRanging method where an attacker can exploit side channel information to determine the presence of specific applications on a device without requiring explicit query permissions or user interaction. The vulnerability stems from the implementation's failure to properly mask timing variations or other observable characteristics that differ between scenarios where an application is installed versus when it is not. This represents a classic information disclosure issue that can be categorized under CWE-200, Information Exposure, with potential implications for privacy and security.
The technical implementation exposes timing discrepancies or other measurable differences in the ranging process that correlate with application installation status. When an application is present on the device, certain Bluetooth beaconing behaviors or system responses differ from those when the application is absent, creating a side channel that can be monitored and analyzed. This vulnerability operates at the system level within the Android framework, specifically affecting the Real-Time Transfer (RTT) service implementation that handles Bluetooth ranging operations. The flaw does not require elevated privileges or user interaction, making it particularly concerning as it can be exploited by any application with Bluetooth permissions or through other means that can trigger the ranging functionality.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable adversaries to build profiles of installed applications on target devices. This information can be leveraged for various malicious purposes including targeted attacks, fingerprinting, and understanding user behavior patterns. The vulnerability affects Android 12 and potentially earlier versions, representing a persistent threat across multiple system releases. From an adversarial perspective, this could align with ATT&CK technique T1082, System Information Discovery, and T1592, Gather Victim Host Information, as it provides systematic ways to enumerate installed applications without direct access to package manager APIs. The lack of user interaction requirements means this vulnerability can be exploited passively, making it particularly dangerous in environments where continuous monitoring is possible.
Mitigation strategies should focus on implementing proper timing uniformity and information flow controls within the Bluetooth ranging implementation. System-level patches should ensure that all ranging operations provide consistent responses regardless of application installation status, eliminating the side channel that enables this information leakage. Device manufacturers should implement defensive measures such as constant-time operations and randomized response delays to prevent timing-based inference. Additionally, developers should consider implementing access controls that prevent unauthorized applications from triggering ranging operations that could expose system information. The vulnerability highlights the importance of secure implementation practices, particularly in system services that handle sensitive communication protocols and the necessity of comprehensive security testing that includes side channel analysis to prevent similar issues in the future.