CVE-2011-4276 in Android
Summary
by MITRE
The Bluetooth service (com/android/phone/BluetoothHeadsetService.java) in Android 2.3 before 2.3.6 allows remote attackers within Bluetooth range to obtain contact data via an AT phonebook transfer.
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Analysis
by VulDB Data Team • 04/20/2017
The vulnerability identified as CVE-2011-4276 represents a critical security flaw in the Android operating system's Bluetooth implementation that specifically affects versions 2.3 through 2.3.5. This weakness resides within the Bluetooth headset service component responsible for managing Bluetooth connections and data transfer operations between Android devices and Bluetooth peripherals. The vulnerability stems from insufficient input validation and access control mechanisms within the AT phonebook transfer functionality, which is a standard Bluetooth protocol used for retrieving contact information from mobile devices.
The technical flaw manifests when an unauthorized remote attacker positioned within Bluetooth range can exploit the lack of proper authentication and authorization checks during phonebook transfer operations. The AT phonebook transfer protocol allows for retrieving contact data including names, phone numbers, and other personal information stored on the device. When the Bluetooth service processes these requests without adequate verification of the requesting device's legitimacy, it exposes sensitive contact information to any nearby Bluetooth-enabled device that can establish a connection and initiate the transfer process. This vulnerability operates at the application layer of the Bluetooth stack and leverages the inherent trust model of Bluetooth connections where devices automatically establish communication without sufficient verification mechanisms.
The operational impact of this vulnerability extends beyond simple data exposure to encompass significant privacy and security implications for Android users. Attackers within Bluetooth range can systematically collect contact information from multiple devices, potentially building comprehensive address books that could be used for social engineering attacks, phishing campaigns, or identity theft. The attack vector requires minimal technical expertise and can be executed automatically by malicious devices, making it particularly dangerous in public environments where users may not be aware of the ongoing data collection. This vulnerability directly violates the principle of least privilege and demonstrates inadequate separation of concerns in the Bluetooth service implementation, allowing unauthorized data access that should be restricted to authenticated users or specific applications.
Organizations and individuals should implement immediate mitigations including updating to Android 2.3.6 or later versions where this vulnerability has been patched, disabling Bluetooth when not in use, and configuring Bluetooth devices to not automatically accept connection requests. The vulnerability aligns with CWE-284 which addresses improper access control, and represents a clear violation of the ATT&CK framework's privilege escalation and credential access techniques. Security professionals should also consider network segmentation approaches to prevent Bluetooth-based attacks and implement monitoring solutions to detect unusual Bluetooth connection patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper security testing for wireless communication protocols and demonstrates how seemingly benign features like phonebook transfer can become significant attack vectors when proper access controls are not implemented.