Conficker

Conficker (also known as Downup, Downadup and Kido) is a computer worm that first showed up in October 2008. It targeted the Microsoft Windows operating system.^[1][2][3] It is not known where the name "conficker" came from. "Internet experts" have guessed that the name comes from a mix between two different words: "configure" and "ficken", the German word for "fuck".^[4]

A description of how Conficker spreads

Conficker was believed to be the worst computer worm since the SQL slammer worm in 2003.^[5] It was estimated 15 million computers were infected with Conficker.^[6][7] The virus was supposed to get worse on April 1, 2009, which caused many people to worry about it. However, there were no bad effects.^[8]

On 13 February 2009, Microsoft offered a $250,000 USD reward for help with finding and arresting the people who created the computer worm.^{[9][10][11][12][13]}