CVE-2018-8218 in Windows
Summary
by MITRE
A denial of service vulnerability exists when Microsoft Hyper-V Network Switch on a host server fails to properly validate input from a privileged user on a guest operating system, aka "Windows Hyper-V Denial of Service Vulnerability." This affects Windows 10, Windows 10 Servers.
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Analysis
by VulDB Data Team • 08/16/2024
The vulnerability identified as CVE-2018-8218 represents a critical denial of service weakness within Microsoft Hyper-V Network Switch functionality that operates at the hypervisor level of virtualized environments. This flaw specifically manifests when the Hyper-V host server fails to adequately validate input data originating from a privileged user operating within a guest virtual machine. The vulnerability impacts Windows 10 and Windows Server operating systems that utilize Hyper-V virtualization capabilities, creating a potential pathway for malicious actors to disrupt normal system operations through carefully crafted inputs that exploit the validation gap in the network switch component.
The technical nature of this vulnerability stems from insufficient input validation mechanisms within the Hyper-V Network Switch module that processes network traffic between virtual machines and the physical network infrastructure. When a privileged user within a guest operating system submits malformed or specially crafted network packets, the host server's network switch component fails to properly sanitize or validate these inputs before processing them. This validation failure creates a condition where the system becomes vulnerable to malformed data that can trigger unexpected behavior in the network switching logic, ultimately leading to system instability and potential denial of service conditions.
From an operational perspective, this vulnerability presents significant risks to organizations relying on Hyper-V virtualization environments, as it allows for potential disruption of network services and system availability. The attack vector requires a privileged user within a guest operating system, which means that the threat actor must first gain access to a virtual machine before being able to exploit this weakness. However, once achieved, the impact can be severe as the vulnerability affects the core network switching functionality of the hypervisor, potentially causing complete network disruption for all virtual machines hosted on the affected system. This vulnerability aligns with CWE-20, which describes improper input validation, and can be categorized under the ATT&CK technique T1499.004 for network disruption attacks.
The implications of this vulnerability extend beyond simple denial of service as it can potentially impact the stability of the entire virtualized infrastructure, affecting multiple virtual machines simultaneously. Organizations utilizing Hyper-V environments with multiple virtual machines may experience cascading failures where a single exploited guest system can cause network disruptions across the entire host server. The vulnerability's impact is particularly concerning in enterprise environments where virtualization is extensively used for hosting critical applications and services. Security professionals must consider this weakness as part of broader virtualization security assessments, particularly when evaluating the resilience of hypervisor components against malicious inputs from compromised guest environments.
Mitigation strategies for CVE-2018-8218 should focus on implementing proper input validation controls within the Hyper-V environment and maintaining up-to-date security patches from Microsoft. Organizations should ensure that all affected Windows systems receive the necessary updates that address the validation gap in the Hyper-V Network Switch component. Additionally, network segmentation and access controls should be implemented to limit the potential impact of a compromised guest system. The vulnerability demonstrates the importance of validating inputs at all levels of the virtualization stack and emphasizes the need for robust security controls in hypervisor environments. Regular security assessments and monitoring of virtualization components should be conducted to identify and remediate similar validation weaknesses that could lead to system instability and service disruption.