Hacker Defender is one of the most widely deployed rootkits in the world. It is a user-mode rootkit that modifies several Windows and Native API functions, which allows it to hide information (files, processes, etc.) from other applications. In addition, Hacker Defender implements a backdoor and port redirector that operates through TCP ports opened by existing services. This means it is not possible to find the hidden backdoor through traditional means, like launching a remote port scan against the compromised machine. This video tutorial presents a guide to its use. For more, watch this hacking how-to.