CVE-2017-4941 Explained : Impact and Mitigation

VMware ESXi, Workstation, and Fusion versions are vulnerable to a stack overflow via authenticated VNC sessions, potentially leading to remote code execution.

Understanding CVE-2017-4941

This CVE involves a vulnerability in VMware ESXi, Workstation, and Fusion that could be exploited through authenticated VNC sessions.

What is CVE-2017-4941?

Prior to specific updates, VMware ESXi (6.0 and 5.5 versions), Workstation (12.x versions), and Fusion (8.x versions) are susceptible to a stack overflow vulnerability via authenticated VNC sessions.

The Impact of CVE-2017-4941

Exploiting this vulnerability could allow an attacker to execute remote code within a virtual machine through an authenticated VNC session.

Technical Details of CVE-2017-4941

This section provides more technical insights into the vulnerability.

Vulnerability Description

The flaw allows an authenticated VNC session to trigger a stack overflow using a specific set of VNC packets.

Affected Systems and Versions

ESXi 6.0 before ESXi600-201711101-SG
ESXi 5.5 ESXi550-201709101-SG
Workstation 12.x before 12.5.8
Fusion 8.x before 8.5.9

Exploitation Mechanism

VNC must be manually enabled in the virtual machine's .vmx configuration file for ESXi exploitation.
ESXi must permit VNC traffic through its built-in firewall.

Mitigation and Prevention

Protecting systems from CVE-2017-4941 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply the necessary security updates provided by VMware.
Disable VNC if not required in ESXi configurations.

Long-Term Security Practices

Regularly monitor VMware security advisories for updates.
Implement network segmentation to limit VNC exposure.

Patching and Updates

Update ESXi to versions ESXi600-201711101-SG or ESXi550-201709101-SG.
Upgrade Workstation to version 12.5.8 or later.
Update Fusion to version 8.5.9 or newer.