How does it work?
A piece of malware essentially looks for any VMware machines on a system and accesses the virtual machine images to place malware that will automatically activate on a system boot-up.
Should I be worried?
Virtualization is the future and malware writers can no longer miss out on compromising virtualized systems just as they do physical ones.
How can I prevent it?
You can prevent such malware with traditional methods, such as anti-virus software which will easily detect virual malware such as Crisis. Using proper endpoint security solutions, whitelisting and locked-down network and system-configurations should help.