CVE-2016-6604 in Exynos fimg2d Driver
Summary
by MITRE
NULL pointer dereference in Samsung Exynos fimg2d driver for Android L(5.0/5.1) and M(6.0) allows attackers to have unspecified impact via unknown vectors.
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Analysis
by VulDB Data Team • 08/07/2020
The Samsung Exynos fimg2d driver vulnerability identified as CVE-2016-6604 represents a critical NULL pointer dereference flaw within the graphics processing subsystem of Android devices running versions 5.0 through 6.0. This vulnerability exists within the hardware abstraction layer responsible for managing 2D graphics operations on Samsung's Exynos chipsets, specifically affecting the fimg2d driver component that handles graphics rendering tasks. The flaw manifests when the driver fails to properly validate input parameters during graphics processing operations, leading to a scenario where a NULL pointer reference is attempted, resulting in system instability or potential privilege escalation.
The technical nature of this vulnerability places it squarely within CWE-476, which categorizes NULL pointer dereference conditions as a fundamental programming error that can lead to system crashes or unauthorized access. The vulnerability operates at the kernel level within the Android operating system's graphics framework, making it particularly dangerous as it can be exploited to disrupt normal system operations or potentially gain elevated privileges. Attackers can trigger this condition through malformed graphics commands or image processing operations that bypass normal input validation mechanisms, causing the driver to attempt to access memory locations that have not been properly initialized.
The operational impact of CVE-2016-6604 extends beyond simple system crashes to potentially enable more sophisticated attack vectors within the Android security model. When a NULL pointer dereference occurs in kernel space, it can result in denial of service conditions that prevent normal device operation, or in more severe cases, may allow attackers to execute arbitrary code with kernel-level privileges. This vulnerability affects devices that utilize Samsung's Exynos 5422 and similar chipsets, impacting a significant portion of Android devices from 2015 and early 2016. The unspecified impact mentioned in the CVE description suggests that depending on the system configuration and exploitation method, attackers could potentially achieve privilege escalation or persistent access to device resources.
Mitigation strategies for this vulnerability require immediate patch deployment through Samsung's security updates, as the flaw exists within the device's core operating system components. Organizations should prioritize updating affected devices to the latest security patches released by Samsung, which typically include enhanced input validation mechanisms and proper NULL pointer checks within the fimg2d driver. Additionally, implementing runtime monitoring solutions that can detect anomalous graphics processing patterns may help identify potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" and demonstrates how kernel-level flaws can be leveraged to gain elevated system privileges. Device manufacturers and security teams should also consider implementing application whitelisting and restricted graphics processing permissions to limit potential exploitation surfaces while awaiting official patches.