The basic problem with trying to detect rootkit infections
is that, where the operating system may have been affected (as with a kernel level
rootkit) it cannot be trusted to find illegitimate modifications of its
own components. It spreads whenever the host program is copied onto a plastic
diskette (now dead), CD, DVD, pen drive from one Remove Computer
Virus, and then loaded into another.
Most of these techniques only detect application level rootkits.