CVE-2018-6962 in Fusion
Summary
by MITRE
VMware Fusion (10.x before 10.1.2) contains a signature bypass vulnerability which may lead to a local privilege escalation.
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Analysis
by VulDB Data Team • 03/14/2023
The vulnerability identified as CVE-2018-6962 affects VMware Fusion version 10.x before 10.1.2 and represents a signature bypass flaw that can potentially enable local privilege escalation. This vulnerability resides within the virtualization software's code signing verification mechanisms, which are critical for maintaining system integrity and preventing unauthorized code execution. The flaw allows an attacker with local access to bypass the legitimate code signature validation process, thereby undermining the security controls designed to prevent malicious software from running with elevated privileges.
The technical implementation of this vulnerability stems from insufficient validation of digital signatures within VMware Fusion's runtime environment. When the system attempts to verify the authenticity of code modules or applications, the signature verification process contains a logical flaw that permits forged or unsigned code to pass validation checks. This weakness specifically impacts the kernel-level components of the virtualization stack where code integrity checks are enforced. The vulnerability aligns with CWE-313, which addresses the improper handling of cryptographic signatures, and represents a critical failure in the cryptographic validation process that should ensure only trusted code executes within the virtualized environment.
The operational impact of this vulnerability extends beyond simple privilege escalation as it creates a persistent backdoor for attackers to maintain elevated access within the virtualized system. An attacker who successfully exploits this vulnerability could potentially execute arbitrary code with root privileges, access sensitive system resources, and establish persistence mechanisms that survive system reboots. The local privilege escalation aspect means that an attacker would need only local user access to potentially gain complete system control, making this vulnerability particularly dangerous in multi-user environments where users might have legitimate access to the virtualization software. This weakness creates a vector for attackers to move laterally within networks where virtualization is extensively used.
Mitigation strategies for CVE-2018-6962 primarily focus on immediate patching of affected VMware Fusion installations to version 10.1.2 or later, which contains the necessary signature validation fixes. System administrators should implement comprehensive monitoring of virtualization environments for unauthorized code execution attempts and establish strict code integrity policies. The vulnerability also highlights the importance of maintaining up-to-date virtualization software and implementing principle of least privilege access controls. Organizations should consider implementing additional security measures such as application whitelisting, enhanced logging of code signature verification events, and regular security assessments of virtualization environments to prevent exploitation of similar signature bypass vulnerabilities. This weakness demonstrates the critical importance of cryptographic validation in maintaining system security boundaries, particularly in virtualized environments where the attack surface is extended.