CVE-2016-2067 in Android
Summary
by MITRE
drivers/gpu/msm/kgsl.c in the MSM graphics driver (aka GPU driver) for the Linux kernel 3.x, as used in Qualcomm Innovation Center (QuIC) Android contributions for MSM devices and other products, mishandles the KGSL_MEMFLAGS_GPUREADONLY flag, which allows attackers to gain privileges by leveraging accidental read-write mappings, aka Qualcomm internal bug CR988993.
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Analysis
by VulDB Data Team • 09/01/2022
The vulnerability described in CVE-2016-2067 resides within the MSM graphics driver component of the Linux kernel version 3.x series, specifically affecting Qualcomm's GPU driver implementation used in MSM devices. This flaw manifests in the improper handling of the KGSL_MEMFLAGS_GPUREADONLY flag, which is a critical memory management parameter designed to control GPU memory access permissions. The issue was discovered within the Qualcomm Innovation Center's Android contributions and impacts various MSM-based devices, making it a significant concern for mobile device security. The vulnerability was internally tracked as CR988993 within Qualcomm's bug tracking system, highlighting its recognition as a serious security concern by the vendor.
The technical flaw occurs when the driver incorrectly processes the KGSL_MEMFLAGS_GPUREADONLY flag, which should enforce read-only memory mappings for GPU operations. Instead, this improper handling results in accidental read-write memory mappings being created when the flag is specified. This misconfiguration allows attackers to manipulate memory permissions in ways that were not intended by the driver's design, effectively creating a privilege escalation vector. The vulnerability specifically targets the memory management subsystem of the GPU driver, where the kernel fails to properly validate or enforce the read-only flag when establishing GPU memory mappings. This creates a situation where attacker-controlled code can gain write access to memory regions that should remain read-only, fundamentally compromising the memory protection mechanisms.
The operational impact of this vulnerability is substantial as it enables local privilege escalation attacks that can elevate user-level processes to kernel-level privileges. Attackers exploiting this vulnerability can leverage the accidental read-write mappings to modify critical kernel memory regions, potentially leading to complete system compromise. The flaw is particularly dangerous because it operates at the kernel level within the GPU driver, which means successful exploitation can bypass traditional user-space security controls. This vulnerability essentially undermines the memory protection boundaries that separate user applications from the kernel, allowing malicious code to manipulate kernel data structures and potentially execute arbitrary code with the highest system privileges. The impact extends beyond simple privilege escalation to potentially enable full system takeover and persistent backdoor installation.
Mitigation strategies for this vulnerability require immediate kernel updates and patches from Qualcomm and device manufacturers, as the flaw exists within core kernel components. System administrators should prioritize patch deployment for all affected MSM-based devices and ensure that kernel versions include the fix for the improper handling of the KGSL_MEMFLAGS_GPUREADONLY flag. Additionally, implementing runtime memory protection mechanisms such as kernel address space layout randomization and stack canaries can provide additional defense-in-depth measures. Organizations should also monitor for any potential exploitation attempts and consider implementing process monitoring to detect suspicious memory access patterns. The vulnerability aligns with CWE-125, which addresses out-of-bounds read conditions, and potentially with CWE-248, concerning uncaught exceptions, as the improper flag handling leads to unexpected memory access behavior. From an ATT&CK perspective, this vulnerability maps to privilege escalation techniques under the T1068 category, specifically targeting kernel-level privilege escalation through memory corruption and permission manipulation.