CVE-2023-5158 in Linux
Summary
by MITRE • 09/25/2023
A flaw was found in vringh_kiov_advance in drivers/vhost/vringh.c in the host side of a virtio ring in the Linux Kernel. This issue may result in a denial of service from guest to host via zero length descriptor.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/16/2023
The vulnerability identified as CVE-2023-5158 resides within the Linux kernel's virtualization subsystem, specifically in the vhost implementation that handles virtio ring operations. This flaw exists in the vringh_kiov_advance function located in drivers/vhost/vringh.c, which represents a critical component in the host-side processing of virtio ring descriptors. The vulnerability manifests when a guest operating system attempts to submit a zero-length descriptor to the virtio ring, which should normally be handled gracefully by the kernel's virtualization layer but instead triggers unexpected behavior.
The technical nature of this vulnerability stems from inadequate input validation within the vringh_kiov_advance function, which processes descriptor chains in the virtio ring mechanism. When a guest submits a descriptor with zero length, the kernel's handling routine fails to properly account for this edge case, leading to potential memory corruption or system instability. This represents a classic case of improper handling of boundary conditions in kernel space code, where the assumption that all descriptors will have valid length values is violated. The flaw operates at the intersection of virtualization security and kernel robustness, where guest-to-host communication pathways become attack vectors for denial of service attacks.
The operational impact of CVE-2023-5158 extends beyond simple service disruption, as it can potentially enable attackers to cause system crashes or hang virtual machines in resource-constrained environments. This vulnerability affects systems running Linux kernels with vhost support, particularly those hosting virtualized workloads where guest operating systems might be untrusted or malicious. The denial of service condition occurs because the kernel's response to zero-length descriptors can lead to infinite loops, memory exhaustion, or invalid memory access patterns that ultimately result in system instability. This issue particularly impacts cloud environments and virtualization platforms where multiple guests share host resources and where a single compromised guest could potentially affect the entire host system.
Mitigation strategies for CVE-2023-5158 should focus on both immediate patching and operational security measures. The primary solution involves applying the relevant kernel security patches that address the improper handling of zero-length descriptors in the vringh_kiov_advance function. Organizations should prioritize updating their Linux kernel versions to include fixes for this vulnerability, particularly in production environments where virtualization is extensively used. Additional defensive measures include implementing strict guest operating system monitoring and resource limiting to prevent single guests from exhausting host resources through malicious descriptor manipulation. This vulnerability aligns with CWE-129, which addresses improper validation of array indices and descriptor lengths, and represents a potential vector for attacks categorized under the ATT&CK technique T1499.004 for network denial of service. System administrators should also consider implementing hypervisor-level controls that can detect and isolate anomalous descriptor patterns, as well as maintaining comprehensive monitoring for system instability indicators that might suggest exploitation attempts.