CVE-2018-9397 in Android
Summary
by MITRE • 12/05/2024
In WMT_unlocked_ioctl of MTK WMT device driver, there is a possible OOB write due to a missing bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 12/19/2024
The vulnerability identified as CVE-2018-9397 resides within the MediaTek WMT (Wireless Module Tranceiver) device driver implementation on Android devices. This flaw manifests in the WMT_unlocked_ioctl function where a critical boundary check is absent, creating a potential out-of-bounds write condition. The issue affects the kernel-level device driver responsible for managing wireless communication modules, specifically those utilizing MediaTek chipsets. Such drivers operate with elevated privileges and handle direct hardware interactions, making any vulnerability within their boundaries particularly concerning for system security.
The technical implementation flaw stems from insufficient input validation within the ioctl (input/output control) interface of the WMT driver. When processing certain ioctl commands, the driver fails to verify that user-supplied data parameters remain within expected memory boundaries before performing write operations. This missing bounds check allows an attacker to craft malicious ioctl requests that can overwrite adjacent memory locations beyond the intended buffer. The vulnerability is classified as a classic buffer overflow scenario where the lack of proper bounds checking enables arbitrary memory corruption, potentially leading to complete system compromise.
The operational impact of this vulnerability extends beyond simple memory corruption as it enables local privilege escalation to system level privileges. An attacker with local access to the device can exploit this flaw without requiring user interaction or additional attack vectors. The exploitation process typically involves crafting specific ioctl commands that trigger the out-of-bounds write condition, which can then be leveraged to overwrite critical kernel data structures or function pointers. This capability allows the attacker to execute arbitrary code with kernel-level privileges, effectively gaining complete control over the device's operating system and all its resources. The vulnerability represents a significant threat in mobile security contexts where kernel-level access can be leveraged to bypass device security measures, access encrypted data, or install persistent backdoors.
Mitigation strategies for CVE-2018-9397 primarily involve applying vendor-provided security patches and firmware updates that address the missing bounds check in the WMT driver implementation. System administrators and device manufacturers should prioritize immediate deployment of these patches to protect affected devices. Additionally, implementing kernel hardening techniques such as stack canaries, address space layout randomization, and kernel address space protection can provide defense-in-depth measures against similar vulnerabilities. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and maps to ATT&CK technique T1068, which covers local privilege escalation through kernel exploits. Regular security audits of kernel drivers and input validation mechanisms should be conducted to identify and remediate similar boundary check deficiencies that could lead to privilege escalation vulnerabilities in mobile operating systems.