The rootkit allowed someone access to this computer. What did they do with that access? You realize that the rootkit was used to deny the user access to files on their system that contain lots of important company data.
If the malicious actors block access to data or threaten to publish the sensitive data unless the client pays them money, that could be a case ransomware. The use of ransomware has been skyrocketing as threat actors have realized it’s safer and easier to rob a virtual location rather than a physical one! Ransomware is one of the largest cybersecurity threats facing industries today.
Blocking a user’s access to data greatly threatens availability. While availability might not seem important, it can be devastating to some organizations. Imagine if a hospital or flight system lost access to their system or data!