CVE-2016-0809 in Android
Summary
by MITRE
Use-after-free vulnerability in the wifi_cleanup function in bcmdhd/wifi_hal/wifi_hal.cpp in Wi-Fi in Android 6.x before 2016-02-01 allows attackers to gain privileges by leveraging access to the local physical environment during execution of a crafted application, aka internal bug 25753768.
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Analysis
by VulDB Data Team • 07/06/2022
The vulnerability described in CVE-2016-0809 represents a critical use-after-free flaw within the Android Wi-Fi subsystem that specifically affects Android 6.x versions prior to February 1, 2016. This issue resides in the wifi_cleanup function located within the bcmdhd/wifi_hal/wifi_hal.cpp file, which forms part of the Android Wi-Fi HAL (Hardware Abstraction Layer) implementation. The vulnerability's classification as a use-after-free indicates a fundamental memory management error where the system attempts to access memory that has already been freed, creating a potential exploitation vector for malicious actors. The flaw is particularly concerning because it requires only local physical access to the device and can be triggered through execution of a crafted application, making it accessible to attackers who can physically interact with the target device.
The technical nature of this vulnerability stems from improper memory management within the Wi-Fi HAL component during the cleanup process of wireless network connections. When the wifi_cleanup function executes, it likely handles the deallocation of memory resources associated with Wi-Fi connection management, but fails to properly validate or manage references to freed memory blocks. This creates a window where an attacker can manipulate the system's memory state to cause the application to access previously freed memory locations, potentially leading to arbitrary code execution. The vulnerability operates at a low level within the Android system, specifically within the Wi-Fi hardware abstraction layer that bridges the operating system with the underlying wireless hardware drivers. This positioning allows successful exploitation to potentially elevate privileges within the Android system, as the Wi-Fi HAL typically operates with elevated permissions to manage hardware resources.
The operational impact of CVE-2016-0809 extends beyond simple privilege escalation, as it represents a significant security weakness that can be exploited in real-world scenarios involving physical access to Android devices. Attackers with physical access to a vulnerable Android 6.x device can leverage this vulnerability to execute malicious code with system-level privileges, potentially compromising the entire device. The vulnerability's exploitation requires minimal prerequisites, only local physical access and the ability to execute a crafted application, making it particularly dangerous in environments where physical security may be compromised. This type of vulnerability is classified under CWE-416 as Use After Free, which is a well-documented weakness in software systems where memory is accessed after it has been freed. The attack surface is particularly relevant in mobile environments where physical access can occur through various means including theft, accidental exposure, or social engineering attacks. The vulnerability's impact is consistent with ATT&CK technique T1068, which covers 'Local Privilege Escalation', where adversaries exploit weaknesses in local system components to gain elevated system privileges.
Mitigation strategies for this vulnerability require immediate patching of affected Android 6.x devices with the security update released by Google on February 1, 2016, which addressed the specific memory management flaw in the Wi-Fi HAL implementation. System administrators and device security teams should prioritize deployment of this patch across all affected Android 6.x devices, particularly those in high-security environments or handling sensitive information. Additionally, organizations should implement monitoring for suspicious Wi-Fi connection behavior and memory access patterns that could indicate exploitation attempts. The vulnerability highlights the importance of proper memory management practices in system-level components and underscores the need for comprehensive security testing of hardware abstraction layers. Device manufacturers should consider implementing additional runtime protections such as memory protection mechanisms and stack canaries to prevent exploitation of similar use-after-free vulnerabilities in future implementations. The remediation process should also include verification that the patched system correctly handles Wi-Fi connection cleanup operations without creating memory access violations. This vulnerability serves as a reminder of the critical security implications that can arise from memory management errors in system-level components and the necessity of rigorous security validation for all system interfaces that interact with hardware resources.