Nimda

Spell it backwards and you will understand its prime targets: yes, the Admin and servers. It was basically a worm and has the record of being the fastest ever virus to spread; it took only 22 minutes to break into the list of top ten most deadly viruses of all times. It basically targeted?internet?servers?and websites, creating a mass crater through which thousands of computers were affected at the same time. Once infected, the systems became exposed to open attacks by the outsiders.