I believe Conficker is one of the most interesting forms of self- updating worm that affected millions of computers including government, businesses, and home computers all over the world which exposed serious vulnerabilities in the world’s digital infrastructure. Mainly, Conficker is an Internet worm that infected millions of computers since it first appeared in November 2008 as one of the largest currently active botnets in the cyberspace. In the past decade, Conficker botnet is ranked as one of the largest and most serious cyber security threats due to the potentially significant damage this worm could do to individual internet users, corporations, governments or critical internet infrastructure. It is a type of computer malware that targets a flaw within the Microsoft Windows operating system. Once it infects a computer, it can link the infected computer to a remote computer controlled by the malware author and then download additional instructions to the infected computer. Conficker uses a number of methods to self-propagate and evade defensive efforts to counter the malware or remediate the computer. The original version released is known as Conficker A, since then, there have been four more versions which are labeled by Microsoft as Variations B, C, D, and E. In February 2, 2010 BBC News Channel reported Manchester Police computers were cut off from national criminal database for more than three days due to Conficker, a malicious worm. According to the Conficker Working group report quote “The exact size of Conficker has been debated since the worm appeared. At its peak, Tom Gaffney of F-Secure estimated that 15 million machines were infected. Others found that number to be too high, but nearly everyone today places the number above five million”. Below is a map showing the affected areas in the world.