Original sentence: However, such assertions are controversial.Hypervisor technology has been suspected to provide certain security invasion capabilities to malware or rootkits by installing themselves as a hypervisor to an operating system.It would thereby intercept any operations of the operating system, which becomes a virtual machine
Edited sentence: However, such assertions have been disputed by others who claim that it would indeed be possible to detect the presence of a hypervisor-based rootkit.Indeed, the difficulties an antivirus program would have removing hypervisor-based malware are similar to the difficulties malware would have infecting a host operating system from the guest.It should be noted that just because malware can use hypervisor technology itself does not necessarily make hypervisors insecure.The use of hypervisor technology by malware and rootkits installing themselves as a hypervisor below the operating system can make them more difficult to detect because the malware could intercept any operations of the operating system (such as someone entering a password) without the antivirus software necessarily being able to detect it (since the malware runs below the entire operating system)