Definition of:rootkit  A type of Trojan that keeps itself, other
files, registry keys and network connections hidden from
detection. It enables an attacker to have "root" access to the
computer, which means it runs at the lowest level of the
machine. A rootkit typically intercepts common API calls. For
example, it can intercept requests to a file manager such as
Explorer and cause it to keep certain files hidden from display,
even reporting false file counts and sizes to the user. Rootkits
came from the Unix world and started out as a set of altered
utilities such as the ls command, which is used to list file
names in the directory (folder).  Legitimate Rootkits? Rootkits
can also be used for what some vendors consider valid purposes.
For example, if digital rights management (DRM) software is
installed and kept hidden, it can control the use of licensed,
copyrighted material and also prevent the user from removing the
hidden enforcement program. However, such usage is no more
welcomed than a rootkit that doe