MyDoom

MyDoom?was instigated somewhere in mid 2004 and it actually prompted US senator to propose the creation of a National Virus Response Centre. The virus attacked in two phases; the first phase infected different Operating Systems, creating inroads and backdoors and making them vulnerable to external users. Once this problem was sorted out, the MyDoom struck again after few months, this time targeting the Search Engines like Google, slowing them down considerably, and crashing a few.