[As ever, this is on the BBC News website for your delectation and delight]
The Conficker worm will be active again on April 1st, according to an analysis of its most recent variant, Conficker.C, by the net security firm CA.
This malicious piece of software, also known as Downup, Downadup and Kido, spreads among computers running most variants of the Windows operating system and turns them into nodes on a multi-million member ‘botnet’ of zombie computers that can be controlled remotely by the worm’s as yet unidentified authors.
Since it first appeared last October it has apparently infected over fifteen million computers around the internet, though even that number is no more than an educated guess because the worm works very hard to disguise its presence on a PC.
Conficker spreads through a security vulnerability in the Windows Server Service that allows a carefully written program to persuade the attacked computer to run malicious code instead of the Microsoft-written software.