CVE-2017-18050 in Android
Summary
by MITRE
In Android for MSM, Firefox OS for MSM, QRD Android, with all Android releases from CAF using the Linux kernel, improper input validation for vdev_map in wma_tbttoffset_update_event_handler(), which is received from firmware, leads to potential buffer overwrite and out of bounds memory read.
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Analysis
by VulDB Data Team • 02/22/2023
This vulnerability exists within the Android operating system and related platforms that utilize the Linux kernel, specifically affecting devices using the Qualcomm Snapdragon chipset. The issue stems from inadequate input validation mechanisms within the wireless management subsystem where the vdev_map parameter is processed. This parameter is received from firmware components and is handled through the wma_tbttoffset_update_event_handler() function. The flaw represents a classic buffer overflow vulnerability that occurs when the system fails to properly validate the size and content of incoming data before processing it. The vulnerability is particularly concerning as it operates at the kernel level where malicious input could potentially lead to arbitrary code execution or system compromise.
The technical implementation of this vulnerability involves a specific function call chain where firmware data flows directly into kernel memory without sufficient bounds checking. When the vdev_map parameter exceeds expected boundaries, the system attempts to write data beyond allocated memory regions, creating opportunities for both buffer overflows and out of bounds memory reads. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which addresses out-of-bounds write vulnerabilities. The attack surface is particularly wide given that this affects multiple Android variants including CAF (Code-Aurora Forum) based systems and Firefox OS implementations.
The operational impact of this vulnerability extends beyond simple memory corruption as it could enable attackers to gain unauthorized access to system resources or potentially execute malicious code with kernel privileges. Attackers could exploit this weakness by crafting malicious firmware responses that contain oversized vdev_map data structures, causing the kernel to write beyond intended memory boundaries. This could result in system instability, denial of service conditions, or more severe compromise scenarios where attackers might escalate privileges or extract sensitive information from kernel memory spaces. The vulnerability affects all Android releases from CAF using the Linux kernel, making it particularly widespread across various device implementations.
Mitigation strategies should focus on implementing proper input validation mechanisms within the wma_tbttoffset_update_event_handler() function to ensure that all incoming vdev_map data adheres to predefined size limits and content constraints. System administrators should prioritize applying security patches from device manufacturers and ensure firmware updates are deployed promptly to address this vulnerability. Network-level monitoring should be implemented to detect anomalous firmware communication patterns that might indicate exploitation attempts. Additionally, memory protection mechanisms such as stack canaries, address space layout randomization, and kernel address space protection should be enabled to reduce the effectiveness of potential exploitation attempts. The vulnerability demonstrates the critical importance of input validation in kernel space operations and aligns with ATT&CK technique T1068, which covers exploitation of remote services and system vulnerabilities.