Giant Internet Worm Set to Change Tactics April 1

That's when many of the poisoned machines will get more aggressive about “phoning home" to the worm's creators over the Internet. When that happens, the bad guys behind the worm will be able to trigger the program to send spam, spread more infections, clog networks with traffic, or try and bring down websites.

Technically, this could cause havoc, from massive network outages to the creation of a cyberweapon of mass destruction that attacks government computers. But researchers who have been tracking Conficker say the date will probably come and go quietly.

More likely, these researchers say, the programming change that goes into effect April 1 is partly symbolic an April Fools' Day tweaking of Conficker's pursuers, who for now have been able to prevent the worm from doing significant damage.