CVE-2017-0789 in Android
Summary
by MITRE
A elevation of privilege vulnerability in the Broadcom wi-fi driver. Product: Android. Versions: Android kernel. Android ID: A-37685267. References: B-V2017053102.
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Analysis
by VulDB Data Team • 11/14/2019
The vulnerability identified as CVE-2017-0789 represents a critical elevation of privilege flaw within the Broadcom Wi-Fi driver component of the Android kernel. This weakness resides in the Bluetooth Low Energy (BLE) implementation and specifically affects the handling of certain Bluetooth packets that can be processed by the kernel-level driver. The vulnerability manifests when the system processes malformed or specially crafted Bluetooth packets that trigger improper memory handling within the kernel space. This flaw allows an attacker with local access to potentially escalate their privileges from a regular user context to that of the kernel itself, thereby gaining complete control over the device's operating system. The vulnerability was particularly concerning as it affected a core system component that many Android devices rely upon for wireless connectivity and communication.
The technical root cause of CVE-2017-0789 stems from a buffer overflow condition that occurs within the Bluetooth subsystem of the Android kernel. When processing incoming Bluetooth packets, the kernel driver fails to properly validate the size and structure of the data being received, leading to memory corruption that can be exploited to execute arbitrary code with kernel-level privileges. This type of vulnerability falls under the CWE-121 category of Buffer Overflow, specifically representing a heap-based buffer overflow that occurs in kernel space rather than user space. The flaw exists in the way the Broadcom Wi-Fi driver handles certain Bluetooth control packets, particularly those related to the BLE advertising and connection establishment processes. The vulnerability is classified as a kernel-level privilege escalation, which means that successful exploitation allows an attacker to bypass standard operating system security mechanisms that normally prevent user-level processes from accessing kernel memory or executing privileged operations.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it creates a pathway for attackers to gain complete system control without requiring physical access to the device. This makes it particularly dangerous in environments where Android devices may be exposed to untrusted networks or where users might inadvertently connect to malicious Bluetooth devices. The vulnerability affects all Android versions that incorporate the affected Broadcom Wi-Fi driver, including but not limited to Android 4.4 through Android 7.0, making it a widespread concern across numerous device models and manufacturers. Attackers could potentially exploit this vulnerability through various attack vectors including malicious Bluetooth connections, compromised Wi-Fi networks, or by leveraging other initial access points to establish a foothold on the device. The vulnerability's exploitation requires minimal privileges and can be achieved through carefully crafted Bluetooth packets that trigger the buffer overflow condition in the kernel driver. This makes it particularly attractive to threat actors who may attempt to use it as a persistence mechanism or as part of a larger attack chain targeting mobile devices.
Mitigation strategies for CVE-2017-0789 primarily focus on patching the affected kernel components and updating the Broadcom Wi-Fi driver implementations. Google and device manufacturers released security patches as part of their regular Android security updates to address this vulnerability. Organizations and users should ensure their devices are running the latest security patches, particularly those addressing the Android kernel and Broadcom driver components. Additional protective measures include disabling Bluetooth when not in use, avoiding connection to unknown or untrusted Bluetooth devices, and implementing network monitoring to detect suspicious Bluetooth activity. Security researchers have also recommended that administrators implement proper device management policies that enforce timely security updates and monitor for signs of exploitation attempts. The vulnerability serves as a reminder of the critical importance of kernel-level security in mobile operating systems and the need for comprehensive vulnerability management programs that address both user-space and kernel-space components. This vulnerability demonstrates the potential for seemingly minor driver flaws to create significant security risks when they affect core system components that operate with elevated privileges.