There’s a quote from Homer Simpson that’s often overused in IT security circles, “Oh, they have the Internet on computers now.” The quote wonderfully captures how surprised people are by things that seem like a natural progression to people who understand a topic deeply. In this case, more and more ransomware groups are creating versions of their ransomware specifically designed to encrypt VMware ESXi systems.
Why? Because if a ransomware actor can encrypt an ESXi server, they can instantly remove dozens or hundreds of machines from the network, creating significantly more chaos. Being able to knock an ESXi server offline allows the attacker to do a lot of damage in a shorter period of time, not just because of the number systems, but also because of the type of data stored on ESXi servers. ESXi systems usually store backups, file storage, code repositories, databases, and other critical files making their encryption a serious business disruption.
But there’s another advantage: Many organizations have virtualized their DR environments. Whether it’s a hosted environment or a Disaster Recovery as a Service (DRaaS), organizations can save a lot of money by going virtual and can restore servers very quickly after a ransomware attack. However, if the DR site is reachable from the network, the ransomware attacker can use that connectivity to access and encrypt the DR servers. This isn't a hypothetical scenario. Unfortunately, it has happened to several ransomware victims
Organizations relying on virtual servers for DR should ensure those servers are fully segmented from the live network, to avoid encryption by a ransomware group. In addition, these systems should have the same security systems installed and monitoring that are applied to live servers. DR servers are critical to ransomware recovery and should be monitored as such.