Rootkits

Rootkit is a malicious software that is used to gain the administrator access to the operating system of the target computer. Traditionally, on the Unix systems, the main administrator account has a username called 'root'. This root user has all the privileges on the operating system. This is how rootkits got their name, since their basic task is to obtain root-level access to the system. The first known rootkit was written by Lane Davis and Riley Dake for SunOS 4.1.1 in 1990. Often rootkits hide their installation by replacing the standard operating system executables and libraries (dlls). Because of this, even if somebody scans the process table of the operating system he/she cannot detect the presence of a rootkit since all that he/she sees are the regular operating system processes.