CVE-2017-15814 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, in msm_flash_subdev_do_ioctl of drivers/media/platform/msm/camera_v2/sensor/flash/msm_flash.c, there is a possible out of bounds read if flash_data.cfg_type is CFG_FLASH_INIT due to improper input validation. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 05/31/2020
This vulnerability exists in the Android kernel-based multimedia subsystem specifically within the camera flash driver component. The flaw resides in the msm_flash_subdev_do_ioctl function located in drivers/media/platform/msm/camera_v2/sensor/flash/msm_flash.c file. The vulnerability stems from inadequate validation of the flash_data.cfg_type parameter when it equals CFG_FLASH_INIT, creating a potential out-of-bounds read condition that can be exploited to extract sensitive information from kernel memory. The issue affects multiple Android variants including MSM Android, Firefox OS for MSM, and QRD Android, all utilizing Linux kernel versions from the Code Aurora Forum. This represents a critical security flaw that can be leveraged by malicious actors with system-level privileges to gain unauthorized access to confidential data stored in kernel memory regions.
The technical implementation of this vulnerability demonstrates a classic buffer over-read scenario where the driver fails to properly validate input parameters before processing them. When CFG_FLASH_INIT is passed as the configuration type, the system does not adequately check the bounds of the flash_data structure, allowing an attacker to manipulate the data structure in a way that causes the kernel to read memory locations beyond the intended buffer boundaries. This improper input validation creates an information disclosure vulnerability that operates at the kernel level, making it particularly dangerous as it can expose sensitive system information, kernel addresses, or other confidential data that should remain protected from user-space access. The vulnerability falls under CWE-125 Out-of-bounds Read, which is classified as a memory safety issue that allows reading memory beyond allocated boundaries.
The operational impact of this vulnerability is significant as it provides a pathway for local information disclosure attacks that require only system execution privileges to exploit. Unlike many vulnerabilities that require user interaction or network access, this flaw can be triggered through direct system-level operations, making it particularly concerning for embedded systems and mobile devices where kernel-level access is often available to malicious applications or compromised processes. The exploitation process does not require any user interaction, which means that an attacker with system-level privileges can silently extract sensitive information from kernel memory without detection. This type of vulnerability directly aligns with ATT&CK technique T1003.002 Credential Dumping: LSASS Memory, as it enables extraction of sensitive kernel memory contents that may contain authentication credentials, system configuration data, or other confidential information. The vulnerability affects a broad range of devices that utilize Qualcomm MSM-based hardware platforms, creating widespread potential impact across multiple device manufacturers and operating system variants.
Mitigation strategies for this vulnerability should focus on implementing robust input validation mechanisms within the flash driver component. The primary fix involves adding proper bounds checking for the flash_data.cfg_type parameter before any memory operations are performed, ensuring that CFG_FLASH_INIT and other configuration types are properly validated against expected values. System administrators and device manufacturers should prioritize applying the latest kernel updates from the Code Aurora Forum and Android security patches that address this specific memory validation issue. Additional protective measures include implementing kernel memory protection features such as stack canaries, kernel address space layout randomization, and enhanced memory access controls to limit the potential damage from such information disclosure vulnerabilities. Organizations should also conduct thorough security assessments of their embedded systems to identify similar input validation flaws in other kernel drivers and subsystems. The vulnerability demonstrates the critical importance of proper input validation in kernel-space code and serves as a reminder of the potential consequences when such validation is insufficient, particularly in mobile device platforms where kernel-level access can be obtained through various attack vectors.