CVE-2016-2439 in Android
Summary
by MITRE
Buffer overflow in btif/src/btif_dm.c in Bluetooth in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-05-01 allows remote attackers to execute arbitrary code via a long PIN value, aka internal bug 27411268.
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Analysis
by VulDB Data Team • 11/06/2018
The vulnerability identified as CVE-2016-2439 represents a critical buffer overflow flaw within the Bluetooth implementation of Android operating systems. This security weakness resides in the btif/src/btif_dm.c source file, which forms part of the Bluetooth Interface Transport (BTIF) framework responsible for managing Bluetooth device connections and pairing operations. The vulnerability specifically affects Android versions 4.x prior to 4.4.4, 5.0.x prior to 5.0.2, 5.1.x prior to 5.1.1, and 6.x prior to the 2016-05-01 security update release. The flaw manifests when the system processes a maliciously crafted PIN value during Bluetooth pairing procedures, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized code execution privileges on affected devices.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. In this case, the buffer overflow occurs during the processing of PIN values in the Bluetooth device management component, specifically when handling authentication requests. The flaw stems from inadequate input validation mechanisms that fail to properly sanitize or limit the length of PIN values accepted during Bluetooth pairing operations. When an attacker provides a PIN value exceeding the allocated buffer size, the excess data overflows into adjacent memory regions, potentially corrupting critical system structures or allowing arbitrary code injection through memory overwrite techniques.
The operational impact of CVE-2016-2439 extends beyond simple remote code execution capabilities, as it represents a significant threat to mobile device security and user privacy. Attackers can exploit this vulnerability without requiring physical proximity or user interaction, making it particularly dangerous in public or shared environments where Bluetooth devices may be paired automatically. The attack vector involves sending a specially crafted long PIN value to an affected Android device during pairing attempts, which can be executed through various means including malicious Bluetooth advertisements or compromised paired devices. This vulnerability enables attackers to potentially gain full control of affected devices, access sensitive user data, install malicious applications, or establish persistent backdoors for further exploitation. The impact is exacerbated by the fact that this vulnerability affects multiple Android versions and device types, creating a wide attack surface that could compromise millions of devices globally.
Mitigation strategies for CVE-2016-2439 should prioritize immediate system updates to the latest Android security patches released by Google, specifically targeting the versions mentioned in the vulnerability description. Organizations and users must ensure that all Android devices are updated to versions containing the patched btif_dm.c implementation that includes proper bounds checking for PIN value processing. System administrators should implement network monitoring solutions to detect anomalous Bluetooth pairing attempts and establish device management policies that require regular security updates. The vulnerability also highlights the importance of input validation and bounds checking in mobile operating system components, aligning with ATT&CK technique T1059.007 for execution through scripting and T1133 for external remote services. Additional defensive measures include disabling unnecessary Bluetooth functionality when not in use, implementing device authentication requirements for Bluetooth pairing, and conducting regular security audits of mobile device configurations to prevent exploitation of similar buffer overflow vulnerabilities in other system components.