Mydoom
The virus was made to be sent in an email with an attachment that carried the virus. When the attachment was opened, the virus would download itself to the computer. The virus can only affect Windows based computers. The virus came with a package that would spam the SCO Group website. SCO had caused arguments within the Linux community for getting copyrights on some open source software. However, only 25% of the infected computers would launch the attack. After the virus has been downloaded, it leaves the computer open to other malware by leaving a "backdoor" open.