CVE-2018-9393 in Android
Summary
by MITRE • 12/04/2024
In procfile_write of drivers/misc/mediatek/connectivity/wlan/gen2/os/linux/gl_proc.c, 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-2018-9393 resides within the MediaTek connectivity driver for wireless local area network devices, specifically in the procfile_write function located at drivers/misc/mediatek/connectivity/wlan/gen2/os/linux/gl_proc.c. This issue represents a classic out-of-bounds write vulnerability that arises from insufficient input validation and bounds checking within the kernel-level driver code. The flaw occurs when the system processes write operations to proc files, which are virtual files in the /proc filesystem used for kernel-to-user space communication and configuration. The missing bounds check allows an attacker to write data beyond the allocated memory boundaries, potentially corrupting adjacent memory regions and compromising system stability.
The technical nature of this vulnerability places it squarely within the CWE-121 category of "Stack-based Buffer Overflow" and aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation." The vulnerability requires system execution privileges for exploitation, meaning that an attacker must already have some level of access to the system to leverage this flaw. However, the lack of user interaction requirement makes it particularly dangerous as it can be exploited automatically without requiring user engagement or specific actions. The affected MediaTek connectivity driver serves as a bridge between the wireless hardware and the Linux kernel, making it a critical component for wireless functionality across various mobile devices and embedded systems.
The operational impact of CVE-2018-9393 extends beyond simple memory corruption, as it provides a pathway for local privilege escalation. When successfully exploited, this vulnerability allows an attacker with local system access to elevate their privileges to kernel level, thereby gaining complete control over the affected device. This escalation is particularly concerning in mobile device contexts where MediaTek processors are widely deployed, as it could enable attackers to bypass security restrictions, access sensitive data, modify system configurations, or even install persistent backdoors. The vulnerability affects devices running Linux-based operating systems with MediaTek connectivity chips, potentially impacting smartphones, tablets, IoT devices, and other embedded systems that utilize this specific driver implementation.
Mitigation strategies for CVE-2018-9393 should focus on both immediate patching and system hardening measures. The primary solution involves applying the vendor-provided kernel patches that implement proper bounds checking in the procfile_write function, ensuring that all input data is validated against the allocated buffer size before any write operations occur. System administrators should prioritize updating the kernel and driver components to versions that contain the fix, particularly in environments where wireless connectivity is managed through MediaTek hardware. Additionally, implementing kernel address space layout randomization and other exploit mitigation techniques can reduce the effectiveness of potential exploitation attempts. Organizations should also consider monitoring for suspicious write operations to proc files and implementing access controls to limit local user privileges where possible, as the vulnerability requires local system access to exploit but does not need user interaction to succeed.