Attackers deliberately crash browsers, impersonate IT staff, and convince employees to install malicious tools that deploy Havoc malware across corporate systems.

source https://www.techradar.com/pro/security/what-begins-as-a-phone-call-from-it-support-ends-with-a-fully-instrumented-network-compromise-this-fake-tech-support-scam-tricks-employees-into-infecting-their-own-company-devices