CVE-2021-0991 in Android
Summary
by MITRE • 12/15/2021
In OnMetadataChangedListener of AdvancedBluetoothDetailsHeaderController.java, there is a possible leak of Bluetooth MAC addresses due to log information disclosure. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12Android ID: A-181588752
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-0991 resides within the AdvancedBluetoothDetailsHeaderController.java component of Android 12 systems, specifically affecting the OnMetadataChangedListener implementation. This flaw represents a critical information disclosure issue where Bluetooth MAC addresses are inadvertently exposed through logging mechanisms, creating a significant security risk for mobile device users. The vulnerability manifests when the system logs Bluetooth metadata information containing MAC address details without proper sanitization or access control measures.
The technical root cause of this vulnerability stems from improper handling of Bluetooth metadata within the Android framework's Bluetooth subsystem. When Bluetooth devices communicate and their metadata changes, the system's AdvancedBluetoothDetailsHeaderController component processes these events through the OnMetadataChangedListener callback mechanism. During this processing, sensitive Bluetooth MAC address information gets logged to system logs without adequate filtering or access restrictions, creating a persistent exposure of device identifiers that adversaries can potentially exploit.
This vulnerability enables local information disclosure attacks where an attacker with system-level privileges can access previously logged Bluetooth MAC addresses, which may be used for tracking, profiling, or further exploitation attempts. The exposure of Bluetooth MAC addresses creates a persistent identifier that can be used to correlate device usage patterns across different networks and time periods, undermining user privacy and device security. The attack surface is particularly concerning as MAC addresses can be used to identify specific devices and track their movements or activities over time.
The operational impact of this vulnerability extends beyond simple information disclosure, as Bluetooth MAC addresses are often used in various security contexts including device authentication, network access control, and tracking mechanisms. Attackers could leverage this information to perform device fingerprinting, conduct targeted attacks, or correlate device usage across multiple environments. This vulnerability aligns with CWE-209, which addresses improper handling of exception information, and represents a specific implementation flaw in Android's Bluetooth logging framework that violates proper security practices for sensitive information handling.
Mitigation strategies for this vulnerability should focus on implementing proper access controls for system logs containing Bluetooth metadata, ensuring that sensitive information such as MAC addresses are either filtered out or properly restricted from unauthorized access. System administrators should implement logging policies that prevent sensitive device identifiers from being stored in accessible log files, and developers should review all Bluetooth metadata logging implementations to ensure proper sanitization of potentially sensitive information. Additionally, Android security updates should address this issue by modifying the logging behavior of Bluetooth metadata handlers to prevent unauthorized disclosure of device identifiers. The remediation approach should align with ATT&CK technique T1083, which addresses system information discovery, as attackers could use this information to gather device-specific details for further exploitation. Organizations should also consider implementing network-level monitoring to detect unusual patterns of Bluetooth MAC address exposure that might indicate exploitation attempts.