Conficker (AKA Downadup, Conflicker) has been the single most persistently irritating piece of malware since 2003’s SQL SLAMMER. Infections of the Conficker worm reached a historical high in May of 2010, accounting for 15% of all malware infections in Ireland, according to Eset’s latest threat trends report.
Currently Conficker is also responsible for representing just under 10% of all global infections. (9.12% for May, 2010).
Estimates suggest conficker has infected millions of PCs worldwide, with reported instances in more than 200 countries. The Conficker Working Group puts the number of currently infected machines at more than 6 million.
Conficker was first detected in November of 2008 and is a worm that targets Windows Computers. Wikipedia states that “Conficker uses flaws in Windows software and Dictionary attacks on administrator passwords to co-opt machines and link them into a virtual computer that can be commanded remotely by its authors. Conficker has since spread rapidly into what is now believed to be the largest computer worm infection since the 2003 SQL Slammer, with more than seven million government, business and home computers in over 200 countries now under its control. The worm has been unusually difficult to counter because of its combined use of many advanced malware techniques”