CVE-2018-5847 in Android
Summary
by MITRE
Early or late retirement of rotation requests can result in a Use After Free condition in all Android releases from CAF (Android for MSM, Firefox OS for MSM, QRD Android) using the Linux Kernel.
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Analysis
by VulDB Data Team • 02/18/2020
The vulnerability identified as CVE-2018-5847 represents a critical use after free condition affecting Android devices that utilize the Linux kernel from the Qualcomm Android for MSM, Firefox OS for MSM, and QRD Android platforms. This flaw manifests when rotation requests undergo early or late retirement processes, creating a scenario where memory previously allocated to a rotation request object is freed but subsequently accessed by other components. The issue stems from improper memory management within the kernel's graphics subsystem, specifically in how rotation requests are handled during their lifecycle. The vulnerability affects all Android releases utilizing these Qualcomm kernel implementations, making it widespread across numerous mobile devices and embedded systems that depend on Qualcomm's hardware platforms.
The technical root cause of this vulnerability lies in the improper handling of reference counting and memory deallocation within the kernel's graphics driver components. When rotation requests are processed, the system maintains references to these objects in memory while they are active. However, under certain conditions involving early or late retirement of these requests, the system may prematurely free the memory associated with a rotation request object while other processes or threads still maintain references to it. This creates a use after free condition that can be exploited to execute arbitrary code or cause system instability. The flaw is particularly dangerous because it operates at the kernel level, providing attackers with elevated privileges and direct access to critical system resources. The vulnerability can be classified under CWE-416 as a use after free condition and may also relate to CWE-125 as an out-of-bounds read scenario.
The operational impact of CVE-2018-5847 extends beyond simple system crashes or instability, potentially enabling sophisticated exploitation techniques that could compromise device security. An attacker could leverage this vulnerability to execute code with kernel-level privileges, potentially gaining complete control over affected devices. The attack surface includes any application or service that interacts with the graphics subsystem or rotation request handling mechanisms, making it particularly dangerous for mobile platforms where numerous applications and system services maintain graphics-related operations. This vulnerability can be exploited through various attack vectors including malicious applications that trigger rotation requests, or through exploitation of other vulnerabilities that can lead to controlled triggering of the problematic code path. The impact is especially severe for devices running on Qualcomm hardware platforms, as these represent a significant portion of the Android ecosystem and are widely deployed across smartphones, tablets, and embedded systems.
Mitigation strategies for CVE-2018-5847 require immediate patching of affected kernel versions and implementation of proper memory management practices within the graphics subsystem. Organizations should prioritize updating all affected Android devices to versions that include fixes for this vulnerability, particularly those running kernel versions that utilize the Qualcomm MSM platforms. System administrators should implement monitoring solutions to detect anomalous behavior that might indicate exploitation attempts, including unusual memory access patterns or unexpected graphics driver behavior. The fix typically involves implementing proper reference counting mechanisms and ensuring that memory deallocation only occurs when all references to an object have been properly released. Security teams should also consider implementing application sandboxing and privilege separation techniques to limit the potential impact of exploitation even if the vulnerability is successfully exploited. Additionally, the vulnerability highlights the importance of comprehensive testing for memory management issues in kernel-level components and adherence to secure coding practices that prevent use after free conditions. This vulnerability serves as a reminder of the critical need for robust memory management in kernel space and the potential consequences of inadequate resource handling in embedded systems.