CVE-2017-5578 in QEMU
Summary
by MITRE
Memory leak in the virtio_gpu_resource_attach_backing function in hw/display/virtio-gpu.c in QEMU (aka Quick Emulator) allows local guest OS users to cause a denial of service (host memory consumption) via a large number of VIRTIO_GPU_CMD_RESOURCE_ATTACH_BACKING commands.
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Analysis
by VulDB Data Team • 09/08/2020
The vulnerability identified as CVE-2017-5578 represents a critical memory management flaw within the QEMU virtualization environment that specifically affects the virtio-gpu component. This issue manifests in the hw/display/virtio-gpu.c source file where the virtio_gpu_resource_attach_backing function fails to properly handle memory allocation and deallocation during GPU resource operations. The flaw enables local users within a guest operating system to exploit a memory leak condition that can be triggered through repeated invocation of VIRTIO_GPU_CMD_RESOURCE_ATTACH_BACKING commands, ultimately leading to excessive memory consumption on the host system.
The technical nature of this vulnerability stems from improper memory handling within the virtual GPU subsystem of QEMU, which operates under the Common Weakness Enumeration framework as a CWE-401: Improper Release of Memory Before Removing Last Reference. The vulnerability occurs when the virtio_gpu_resource_attach_backing function processes guest requests to attach backing storage to GPU resources without adequately validating or cleaning up previously allocated memory structures. This memory leak directly impacts the host system's memory management as the guest operating system can repeatedly send resource attachment commands, causing the host to continuously allocate memory without proper deallocation, leading to gradual memory exhaustion.
From an operational perspective, this vulnerability presents a significant denial of service risk that can severely impact system availability and performance. Local guest OS users with access to virtual GPU resources can systematically consume host memory resources through repeated command execution, potentially leading to system instability or complete system crashes. The attack vector requires only local access within the guest environment, making it particularly dangerous as it can be exploited by any user with guest privileges. The impact extends beyond simple resource exhaustion as it can affect other virtual machines running on the same host, creating cascading failures that compromise the entire virtualization infrastructure. This vulnerability aligns with the MITRE ATT&CK framework under the Tactic of Resource Exhaustion and specifically maps to the technique of Process Injection and Memory Exhaustion.
The mitigation strategy for CVE-2017-5578 requires immediate implementation of QEMU version updates that contain patches addressing the memory leak in the virtio-gpu subsystem. System administrators should prioritize patching affected QEMU installations, particularly those running virtualized environments with GPU virtualization enabled. Additional defensive measures include implementing resource monitoring and limiting guest access to GPU resource operations through proper access controls and virtualization policies. Organizations should also consider implementing memory usage alerts and automated response mechanisms to detect and mitigate memory exhaustion attacks. The vulnerability highlights the importance of proper memory management in virtualization components and underscores the need for comprehensive security testing of hypervisor and virtual device implementations. Network segmentation and privilege separation can help limit the potential impact of such vulnerabilities by reducing the attack surface available to local guest users.