CVE-2022-33729 in Mobile Device
Summary
by MITRE • 08/05/2022
Improper restriction of broadcasting Intent in ConfirmConnectActivity of?NFC prior to SMR Aug-2022 Release 1 leaks MAC address of the connected Bluetooth device.
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Analysis
by VulDB Data Team • 08/31/2022
The vulnerability identified as CVE-2022-33729 represents a critical security flaw in the Android operating system's NFC implementation prior to the SMR August 2022 security release. This issue specifically affects the ConfirmConnectActivity component within the NFC subsystem and demonstrates a significant failure in proper intent broadcasting restrictions. The vulnerability arises from insufficient validation mechanisms that allow malicious actors to intercept and extract sensitive Bluetooth MAC addresses through improperly restricted intent broadcasts. The flaw exists in the NFC framework's handling of connection confirmation activities where the system fails to properly sanitize or restrict the scope of broadcast intents that contain Bluetooth device identification information.
The technical implementation of this vulnerability stems from the improper handling of Android Intents within the NFC service layer. When a Bluetooth device connects to an Android device via NFC, the system generates a ConfirmConnectActivity that broadcasts information about the connection. However, the intent broadcast mechanism lacks proper access control checks and scope limitations that would normally prevent unauthorized applications from receiving these broadcasts. This misconfiguration allows any application with appropriate permissions to intercept the broadcast and extract the MAC address of the connected Bluetooth device, effectively bypassing the normal security boundaries that should protect this sensitive information. The flaw is categorized under CWE-200 Information Exposure and represents a direct violation of the principle of least privilege in Android's security architecture.
The operational impact of this vulnerability extends beyond simple information disclosure, creating potential attack vectors for sophisticated adversaries. An attacker with a malicious application installed on a compromised device could continuously monitor NFC connection events and extract Bluetooth MAC addresses from nearby devices. This information can be used for device tracking, fingerprinting, and correlation attacks across different environments. The leaked MAC addresses provide attackers with persistent identifiers that can be used to track user movements, build behavioral profiles, and potentially facilitate more advanced attacks such as man-in-the-middle operations or targeted social engineering campaigns. The vulnerability affects all Android devices running versions prior to the SMR August 2022 security patch, making it a widespread concern across numerous device models and manufacturers.
Mitigation strategies for CVE-2022-33729 primarily focus on applying the appropriate security patches released by Google as part of the SMR August 2022 update cycle. Organizations and device manufacturers should prioritize immediate deployment of the security update to remediate the vulnerability. Additionally, system administrators should implement network monitoring to detect unusual patterns of intent broadcast activity that might indicate exploitation attempts. The Android security model should be enhanced with stricter intent broadcast restrictions, particularly for components handling sensitive device connection information. This includes implementing proper permission checks, using explicit intent receivers, and ensuring that broadcast intents are scoped appropriately to prevent unauthorized access. Organizations should also consider implementing application whitelisting policies and regular security audits of NFC-related components to prevent similar vulnerabilities from emerging in custom Android builds or third-party applications that interact with NFC services. The vulnerability highlights the importance of proper intent handling in mobile security frameworks and serves as a reminder of the critical need for comprehensive security testing of system-level components that handle sensitive device information.