What kind of a threat is a rootkit?
A rootkit is a program (or set of programs) designed to hide itself and possibly other, companion programs from being detected on an infected computer. Originally the term was used to describe existing binary program files on UNIX-based systems which had been modified to hide the presence of unauthorized users, allowing them to re-enter the system at any time with “root” privileges (the highest level allowed on a UNIX system). Today, the term rootkit is most often used to describe discreet programs for Windows-based systems that use “stealth” techniques to mask their own presence as well as that of other software such as adware, keyloggers, remote access tools, spyware and other forms of malicious software. While this technique is not new, it has become more prevalent today. Rootkits allow attackers to stay in control of affected computers longer, which means increased access to information from the compromised host and possibly a better revenue stream from adware and browser hijacking
