CVE-2021-21985 : What You Need to Know

A remote code execution vulnerability has been identified in VMware vCenter Server and VMware Cloud Foundation. Attackers with network access to port 443 can exploit this issue to execute commands with unrestricted privileges on the underlying operating system.

Understanding CVE-2021-21985

This CVE, published on May 26, 2021, presents a critical security threat to VMware vCenter Server and Cloud Foundation users due to a remote code execution vulnerability in the vSphere Client.

What is CVE-2021-21985?

The vSphere Client (HTML5) hosts a remote code execution vulnerability attributed to the lack of input validation in the Virtual SAN Health Check plug-in, which remains activated by default in vCenter Server. This flaw can be leveraged by malicious actors connecting to port 443.

The Impact of CVE-2021-21985

Exploiting this vulnerability allows threat actors to execute arbitrary commands with elevated permissions on the underlying OS, potentially leading to a complete system compromise. As a result, sensitive information and critical infrastructure may be at risk.

Technical Details of CVE-2021-21985

This section delves into the specifics of the vulnerability affecting VMware vCenter Server and VMware Cloud Foundation.

Vulnerability Description

The vulnerability arises from inadequate input validation in the Virtual SAN Health Check plug-in, enabling remote code execution through the vSphere Client (HTML5).

Affected Systems and Versions

VMware vCenter Server versions 7.x before 7.0 U2b, 6.7 before 6.7 U3n, 6.5 before 6.5 U3p, and VMware Cloud Foundation versions 4.x before 4.2.1, 3.x before 3.10.2.1 are susceptible to this vulnerability.

Exploitation Mechanism

Threat actors with network access to port 443 can exploit this vulnerability by sending crafted requests to the Virtual SAN Health Check plug-in, initiating remote code execution attacks.

Mitigation and Prevention

To safeguard systems from the risks posed by CVE-2021-21985, immediate actions and long-term security measures are necessary.

Immediate Steps to Take

Organizations are advised to apply security patches promptly, restricting network access, and monitoring port 443 for suspicious activities to mitigate the risk of exploitation.

Long-Term Security Practices

Implementing stringent input validation mechanisms, conducting regular security audits, and educating personnel on security best practices can help prevent similar vulnerabilities in the future.

Patching and Updates

Ensure that affected systems are updated with the latest patches released by VMware to address the CVE-2021-21985 vulnerability.