CVE-2019-1399 in Windows
Summary
by MITRE
A denial of service vulnerability exists when Microsoft Hyper-V 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 CVE ID is unique from CVE-2019-0712, CVE-2019-1309, CVE-2019-1310.
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Analysis
by VulDB Data Team • 02/11/2024
The vulnerability described in CVE-2019-1399 represents a critical denial of service weakness within Microsoft Hyper-V virtualization platform that specifically affects host server systems running Windows operating systems. This flaw exists in the validation mechanisms that govern how Hyper-V processes input from guest operating systems, creating a scenario where malicious or compromised privileged users within a virtual machine can exploit this weakness to disrupt normal operations of the host system. The vulnerability is particularly concerning because it leverages the trust relationship between host and guest environments, allowing an attacker with elevated privileges in a guest VM to potentially cause system-wide disruptions that could impact multiple virtualized workloads running on the same physical hardware.
The technical root cause of this vulnerability stems from insufficient input validation within Hyper-V's virtualization layer, specifically in how the system handles privileged user requests originating from guest operating systems. When a guest VM user with sufficient privileges attempts to manipulate certain virtual hardware interfaces or memory management operations, the host Hyper-V component fails to properly sanitize or validate the incoming parameters before processing them. This lack of proper validation creates opportunities for malformed or malicious input to cause unexpected behavior in the host system's virtualization engine, potentially leading to system crashes, resource exhaustion, or complete service unavailability. The flaw operates at the hypervisor level where guest-to-host communication occurs, making it particularly dangerous as it can affect the stability of all virtual machines running on that particular host server.
The operational impact of CVE-2019-1399 extends beyond simple system disruption to potentially compromise entire virtualized infrastructures, especially in enterprise environments where multiple VMs share the same physical host resources. Attackers could exploit this vulnerability to cause cascading failures across multiple virtual machines, leading to significant business disruption and potential data loss. The vulnerability is particularly problematic in cloud computing environments where virtualization density is high, as a single compromised guest VM could potentially affect the availability of services for numerous other tenants sharing the same infrastructure. Organizations running Hyper-V environments without proper patch management or monitoring systems could experience extended downtime, service degradation, or unauthorized access to critical infrastructure components. The vulnerability's classification under CWE-20, which addresses "Improper Input Validation," underscores the fundamental security principle that all inputs from untrusted sources must be carefully validated before processing.
Mitigation strategies for CVE-2019-1399 should focus on immediate patch deployment from Microsoft as the primary defense mechanism, alongside enhanced monitoring and access control measures. Organizations must ensure that all Hyper-V host systems receive security updates promptly, particularly since this vulnerability affects the core virtualization functionality that underpins modern cloud and data center environments. System administrators should implement comprehensive monitoring solutions that can detect anomalous behavior patterns in virtual machine resource usage or host system performance that might indicate exploitation attempts. Additionally, implementing network segmentation and limiting guest VM privileges can reduce the potential impact of this vulnerability by minimizing the attack surface available to malicious users. The ATT&CK framework categorizes this type of vulnerability under the 'Defense Evasion' and 'Execution' tactics, as attackers can leverage it to maintain persistence or escalate privileges within virtualized environments. Organizations should also consider implementing micro-segmentation strategies and regular security assessments to identify and remediate similar validation weaknesses in their virtualization infrastructure, as this vulnerability demonstrates the critical importance of maintaining robust input validation mechanisms at all levels of the system architecture.