CVE-2017-0193 in Windows
Summary
by MITRE
Windows Hyper-V in Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, 1703, and Windows Server 2016 allows an attacker to gain elevated privileges on a target guest operating system when Windows Hyper-V instruction emulation fails to properly enforce privilege levels, aka "Hypervisor Code Integrity Elevation of Privilege Vulnerability".
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Analysis
by VulDB Data Team • 12/27/2020
The vulnerability identified as CVE-2017-0193 represents a critical privilege escalation flaw within Microsoft Windows Hyper-V virtualization components that affects multiple operating system versions including Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, 1703, and Windows Server 2016. This vulnerability specifically targets the hypervisor code integrity mechanisms that are responsible for maintaining proper privilege separation between the host operating system and guest virtual machines, creating a potential pathway for attackers to execute malicious code with elevated privileges. The flaw stems from insufficient enforcement of privilege levels during instruction emulation processes within the Hyper-V virtualization environment.
The technical implementation of this vulnerability occurs when Windows Hyper-V fails to properly validate and enforce privilege boundaries during the emulation of certain instructions that are typically executed in a privileged context. This failure allows an attacker running within a guest operating system to potentially execute code that would normally be restricted to the hypervisor level, effectively bypassing the security isolation that virtualization is designed to provide. The vulnerability manifests through improper handling of privilege level checks within the hypervisor's instruction emulation subsystem, which can be exploited by malicious code within the guest environment to escalate privileges to the highest system level. This represents a fundamental breakdown in the virtualization security model where the hypervisor fails to maintain its role as a trusted security boundary.
The operational impact of CVE-2017-0193 is severe and potentially devastating for organizations relying on Hyper-V virtualization environments, as successful exploitation can lead to complete system compromise from within a guest VM. Attackers can leverage this vulnerability to gain SYSTEM-level privileges within the guest operating system, potentially enabling them to access sensitive data, install persistent backdoors, or move laterally within the network. The vulnerability affects the core security architecture of Hyper-V implementations, making it particularly dangerous in environments where multiple virtual machines share the same physical host. Organizations running virtualized environments are at significant risk of unauthorized privilege escalation attacks that could result in data breaches, system compromise, and complete loss of virtualization security isolation. The attack vector is particularly concerning because it requires minimal privileges within the guest system to initiate the exploit, making it accessible to attackers who may have already gained initial access through other means.
Mitigation strategies for CVE-2017-0193 should focus on immediate patch deployment through Microsoft's regular security updates, as the vulnerability was addressed in the July 2017 security bulletin. Organizations should implement comprehensive monitoring for suspicious privilege escalation activities within virtualized environments and ensure that all Hyper-V hosts are updated with the latest security patches. Network segmentation and least privilege principles should be enforced to limit the potential damage from successful exploitation, while virtual machine templates should be regularly audited for proper security configurations. The vulnerability aligns with CWE-284, which describes improper access control in software systems, and maps to ATT&CK technique T1055 for privilege escalation through hypervisor manipulation. System administrators should also consider implementing additional security controls such as hypervisor hardening, regular security assessments, and monitoring for anomalous behavior that could indicate exploitation attempts. Organizations should conduct thorough risk assessments to determine the potential impact of this vulnerability on their specific environments and develop incident response procedures to address potential exploitation attempts.