CVE-2017-5552 in QEMU
Summary
by MITRE
Memory leak in the virgl_resource_attach_backing function in hw/display/virtio-gpu-3d.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-2017-5552 represents a critical memory management flaw within the QEMU virtualization environment that specifically targets the virtio-gpu-3d component. This issue manifests in the virgl_resource_attach_backing function located in the hw/display/virtio-gpu-3d.c source file, where improper memory handling allows malicious guest operating systems to exploit a memory leak condition. The vulnerability is particularly concerning because it operates within the virtualized graphics subsystem that facilitates 3D graphics acceleration in virtual machines, making it accessible to local users within the guest environment who possess the ability to issue specific commands to the virtio-gpu device.
The technical implementation of this vulnerability stems from inadequate memory cleanup procedures within the resource attachment mechanism of the virtio-gpu driver. When guest operating systems repeatedly execute VIRTIO_GPU_CMD_RESOURCE_ATTACH_BACKING commands, the system fails to properly release previously allocated memory segments associated with graphics resources. This memory leak accumulates over time as the guest continues to request additional backing resources for GPU operations, leading to progressive host memory consumption. The flaw essentially creates a scenario where each successful command execution results in memory allocation without corresponding deallocation, allowing the guest to gradually exhaust available host memory resources through repeated command issuance.
The operational impact of this vulnerability extends beyond simple resource exhaustion, creating significant security and stability concerns for virtualized environments. Local guest users can leverage this vulnerability to perform a denial of service attack against the host system by consuming excessive memory resources, potentially causing system instability, performance degradation, or complete system crashes. The attack vector is particularly dangerous because it requires minimal privileges within the guest environment and can be executed programmatically, making it an attractive target for malicious actors seeking to disrupt virtualized services. This vulnerability directly impacts the integrity of virtualization security models where guest isolation is expected to prevent one guest from affecting the host system's stability.
This memory leak vulnerability aligns with CWE-401, which specifically addresses improper resource management and memory leaks in software systems. The flaw demonstrates characteristics of the broader class of issues involving resource exhaustion attacks that can be categorized under ATT&CK technique T1499.001, which covers network denial of service attacks. The vulnerability also reflects common issues in virtualization security where hypervisor components must properly validate and sanitize guest input to prevent resource manipulation attacks. Organizations using QEMU-based virtualization platforms face particular risk as this vulnerability can be exploited without requiring elevated privileges in the guest environment, making it a significant concern for multi-tenant cloud deployments and enterprise virtualization infrastructures.
Mitigation strategies for CVE-2017-5552 should focus on both immediate patching and operational hardening measures. The primary solution involves applying the official QEMU patches that address the memory leak in the virgl_resource_attach_backing function by implementing proper memory cleanup procedures for GPU resource operations. Additionally, system administrators should implement monitoring solutions to detect unusual memory consumption patterns in virtualized environments, particularly around graphics resource allocation. Network segmentation and resource limits for virtual machines can provide additional protection layers, while regular security assessments of virtualization components help identify similar vulnerabilities. Organizations should also consider implementing guest isolation measures and restricting guest access to potentially dangerous GPU commands when such access is not strictly necessary for legitimate operations.