A VMware vulnerability with a severity rating of 9.8 out of 10 is under active exploitation. At least one reliable exploit has gone public, and there have been successful attempts in the wild to compromise servers that run the vulnerable software.
The vulnerability, tracked as CVE-2021-21985, resides in the vCenter Server, a tool for managing virtualization in large data centers. A VMware advisory published last week said vCenter machines using default configurations have a bug that, in many networks, allows for the execution of malicious code when the machines are reachable on a port that is exposed to the Internet.
Code execution, no authentication required
On Wednesday, a researcher published proof-of-concept code that exploits the flaw. A fellow researcher who asked not to be named said the exploit works reliably and that little additional work is needed to use the code for malicious purposes. It can be reproduced using five requests from cURL, a command-line tool that transfers data using HTTP, HTTPS, IMAP, and other common Internet protocols.