Researchers at GuardiCore discovered that a VMWare API can be abused by vSphere users with limited privileges to access the guest operating system without authentication.

This discovery was made while evaluating VMWare’s Virtual Infrastructure eXtension (VIX) API. This tool allows users to write scripts to automate VM operations and manipulate files within the guest OS.

Security researchers have revealed that an attacker can abuse the vulnerability to gain full control of the guest OS, including for arbitrary code execution with elevated privileges, lateral movement across the targeted data center- including to isolated networks, and data theft.

This vulnerability affects guest machines running ESXi 5.5 and VMWare tools with any prior version to version 10.1.0.

In order for an attacker to exploit this flaw, basic knowledge of how the VIX API works and a limited vSphere account is required.  The account must have the “Virtual Machine -> Configuration -> Advanced,” “Virtual Machine -> Interaction -> Guest Operating System Management by VIX API” and the “Host -> Configuration -> Advanced Settings” privileges for the attack to be successful.

This means that a malicious insider is very likely to be the culprit of such an attack. This vulnerability has proven to quite useful for breaking network segmentation, which is a critical component for virtual machines.

VMware published an advisory yesterday, identifying the vulnerability as CVE-2017-4919 with a high severity rating. The problematic functionality in the VIX API can be disabled manually in the case of VMware Tools 9.10.0 through 10.0.x. Starting with VMware Tools 10.1.0, the function has been disabled.

Maintaining a vulnerability free environment is essential to protect sensitive data from hackers or malicious insiders. The Center for Internet Security is the worldwide industry standard for secure configuration guidance, developing comprehensive, consensus-derived checklists to help identify and mitigate known security vulnerabilities across a wide range of platforms, including VMWare.

NNT has access to thousands of CIS Benchmark reports ready to download now to help mitigate know vulnerabilities found within your IT environment. Click here to access these CIS Benchmark Reports


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