A Remote Administration Tool is a special kind of hacker spyware, used for remote access and control of other people’s computers. The attacker infects the PC via the e-mail or File and Print Sharing. A "server" allows him to connect via a "client" on his own machine. The functions of a RAT may vary, depending on the needs of the hacker. Some RATs can’t really harm your PC and the only purpose they were made for is hooliganism. But some versions can steal vital information, delete files and even crash your system. Several versions (RAD 1.2.3) appeared in the internet from September 2000 to September 2002. The pest is written in Visual Basic programming language. The author is a hacker called Acidpool.