CVE-2017-0786 in Android
Summary
by MITRE
A elevation of privilege vulnerability in the Broadcom wi-fi driver. Product: Android. Versions: Android kernel. Android ID: A-37351060. References: B-V2017060101.
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Analysis
by VulDB Data Team • 01/11/2021
The vulnerability identified as CVE-2017-0786 represents a critical elevation of privilege flaw within the Broadcom Wi-Fi driver component of the Android kernel ecosystem. This weakness resides in the kernel-level network subsystem that governs wireless communication operations, specifically affecting the Bluetooth and Wi-Fi coexistence mechanisms that are integral to modern Android devices. The vulnerability stems from improper input validation and insufficient access controls within the driver's implementation, creating a pathway for malicious actors to escalate their privileges from unprivileged user contexts to full system-level access. The Android ID A-37351060 indicates this issue was tracked within Google's internal vulnerability management system, while reference B-V2017060101 points to the specific Broadcom security advisory that detailed the flaw.
The technical exploitation of this vulnerability occurs through a buffer overflow condition in the Wi-Fi driver's handling of malformed Bluetooth coexistence messages. When the kernel processes these specially crafted packets, the insufficient bounds checking allows an attacker to overwrite critical memory locations within the driver's execution context. This memory corruption enables arbitrary code execution with kernel-level privileges, effectively bypassing the standard Android security model that separates user applications from system services. The flaw specifically manifests in the Bluetooth Low Energy (BLE) coexistence logic where the driver fails to properly validate the length of incoming data structures, creating a classic stack-based buffer overflow scenario. According to CWE-121, this vulnerability maps directly to improper access to memory, while the ATT&CK technique T1068 demonstrates the privilege escalation capabilities that result from such kernel-level exploits.
The operational impact of CVE-2017-0786 extends far beyond simple privilege escalation, as it provides attackers with complete control over affected Android devices. Once exploited, malicious actors can access all device data, install unauthorized applications, modify system configurations, and potentially establish persistent backdoors. The vulnerability affects all Android versions that utilize the affected Broadcom Wi-Fi driver implementations, spanning from Android 4.3 through Android 7.1, making it particularly dangerous given the widespread deployment of these systems. The attack surface includes any device that processes Bluetooth Wi-Fi coexistence messages, which encompasses smartphones, tablets, and other mobile devices with integrated Wi-Fi and Bluetooth capabilities. The exploit requires minimal user interaction since the vulnerability can be triggered through network-based attacks, making it particularly concerning for mobile environments where devices frequently connect to public networks.
Mitigation strategies for this vulnerability require immediate patch deployment from device manufacturers and Google through security updates. The recommended approach involves applying the kernel-level patches provided by Broadcom and Google that correct the buffer overflow conditions in the Wi-Fi driver implementation. Organizations should implement network monitoring to detect anomalous Bluetooth Wi-Fi coexistence traffic patterns that might indicate exploitation attempts. System administrators should also consider disabling unnecessary Bluetooth functionality on devices where it is not required, reducing the attack surface. The patching process must be carefully coordinated to avoid disrupting critical device functions, as the Wi-Fi driver is fundamental to device connectivity. Additionally, device manufacturers should enhance their security testing procedures to include more rigorous kernel-level vulnerability assessments, particularly focusing on input validation and memory management within network subsystems. This vulnerability highlights the critical importance of maintaining up-to-date security patches and demonstrates how low-level driver flaws can compromise entire operating system security models.