Conficker, also known as "Downup", "Downadup" and "Kido", is a computer worm that surfaced in October 2008 and targets the Microsoft Windows operating system. The worm exploits a previously patched vulnerability in the Windows Server
service used by Windows 2000, Windows XP, Windows Vista, Windows Server 2003, Windows Server 2008, Windows 7 Beta, and Windows Server 2008 R2 Beta. The worm has been unusually difficult for network operators and law enforcement to counter because of its combined use of advanced malware techniques.
* Account lockout policies being reset automatically.
* Certain Microsoft Windows services such as Automatic Updates, Background Intelligent Transfer Service (BITS), Windows Defender and Error Reporting Services disabled.
* Domain controllers responding slowly to client requests.
* Congestion on local area networks.
* Web sites related to antivirus software becoming inaccessible.