Rootkits refer to the cloaking techniques and methods that, when combined with Trojans, allow attackers undetectable remote administrative access. Their concealment strategies involve modifying system code and processes that would normally detect or prevent remote access. Rootkits alter basic system functions and foundations in order to disguise unauthorized activity.

Keystroke logging, or keylogging, refers to the process of capturing and recording users computer keystrokes without their express consent. The most threatening keyloggers allow an attacker to remotely monitor victim’s recorded keystrokes.

Spyware is software designed with the malicious intent of taking partial control of, and generally disrupting, users interaction with a system. Often, there is a financial motive behind spyware creation and distribution, but this usually comes at the expense of the infected user’s experience.

While some adware can consist of merely harmless advertisements, other adware can be much more destructive. Abusive adware can cause: excessive pop-up ads; serious decrease in system performance; the manipulation of Web sites; the delivery of spyware and other malware; and more. Many freeware and shareware programs include adware, though most users don’t know about it until after they download. And once adware is downloaded to a system, it can be nearly impossible to get rid of.

Browser Hijacking software, or hijackware is a form of malware that modifies Internet browser settings without permission in order to redirect users to websites that they would not normally visit. Hijackware can change users home page and search page, as well as add sites to their favorites folder.