CVE-2016-10029 in QEMU
Summary
by MITRE
The virtio_gpu_set_scanout function in QEMU (aka Quick Emulator) built with Virtio GPU Device emulator support allows local guest OS users to cause a denial of service (out-of-bounds read and process crash) via a scanout id in a VIRTIO_GPU_CMD_SET_SCANOUT command larger than num_scanouts.
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Analysis
by VulDB Data Team • 11/12/2024
The vulnerability identified as CVE-2016-10029 resides within QEMU's Virtio GPU Device emulator implementation, representing a critical security flaw that undermines system stability through improper input validation. This issue affects virtualized environments where guest operating systems interact with emulated graphics hardware, specifically targeting the virtio_gpu_set_scanout function that processes VIRTIO_GPU_CMD_SET_SCANOUT commands. The vulnerability manifests when a local guest OS user submits a malformed scanout id parameter that exceeds the valid range defined by num_scanouts, creating a condition where the emulator fails to properly bounds-check user-supplied data before processing it.
The technical flaw constitutes an out-of-bounds read condition that occurs when the virtio_gpu_set_scanout function fails to validate that the scanout id parameter falls within acceptable limits. This validation failure allows attackers to specify a scanout id value that surpasses the maximum allowed number of scanouts, leading to memory access violations and subsequent process crashes. The vulnerability operates at the intersection of virtualization security and graphics driver emulation, where guest operating systems can leverage this flaw to execute denial of service attacks against the host system's virtualized graphics environment. According to CWE classification, this represents a CWE-129: Improper Validation of Array Index vulnerability, where insufficient bounds checking leads to memory corruption and system instability.
The operational impact of CVE-2016-10029 extends beyond simple service disruption, as it enables local privilege escalation within virtualized environments and can potentially be exploited to compromise the entire virtualization stack. When exploited, the vulnerability causes immediate process termination and system instability that can affect multiple virtual machines sharing the same host resources. The attack surface is particularly concerning in cloud computing environments where multiple tenants share infrastructure, as a single compromised guest OS could potentially disrupt services for other virtual machines. This vulnerability aligns with ATT&CK technique T1499.001: Network Denial of Service, where adversaries leverage system weaknesses to create service interruptions that can cascade through virtualized infrastructures.
Mitigation strategies for CVE-2016-10029 focus primarily on updating QEMU to versions that include proper bounds checking for scanout id parameters in the Virtio GPU implementation. System administrators should implement strict virtualization environment monitoring to detect anomalous behavior patterns that may indicate exploitation attempts, while also applying network segmentation to limit the potential impact of successful attacks. The fix typically involves implementing comprehensive input validation that ensures scanout id values remain within the acceptable range defined by num_scanouts, preventing out-of-bounds memory access. Organizations should also consider implementing virtualization-specific security controls such as hypervisor hardening, regular security assessments, and maintaining updated virtual machine images to prevent exploitation of known vulnerabilities. Additionally, monitoring for unusual scanout command patterns and implementing automated response mechanisms can help detect and mitigate exploitation attempts before they cause significant disruption to virtualized services.