Sightings have already been reported in the UK, US, Israel and Iceland of the latest "macro virus", which infects documents written with Microsoft's Word word-processing program - possibly the most widely-used piece of office software in the world.
The Wazzu virus randomly moves, changes or adds words to a document, and occasionally inserts the word "wazzu". It is spread by opening an "infected" document - though there is no way for the hapless user to know ahead of time if the document poses a risk, unless they have one of a new breed of virus-checking programs to guard against it.
The effect would be disastrous in a large document, such as a contract, which could be riddled with gibberish. Also, any further documents written with an infected program will also wazzu at random. Anybody who receives a Word document written by an infected program will in turn be infected too.
"Wazzu appears to be the most advanced macro virus to date," said Shannon Jenkins, of Touchstone Software, in London. "And it is spreading like wildfire."
"It is already the second most common macro virus," said Graham Cluley, senior technology consultant at Dr Solomon's Anti-virus in Aylesbury.
Macro viruses consist of a series of instructions embedded in a document which tell the user's machine to automatically carry out various instructions. Unlike standard viruses, macro viruses are not limited to one particular make of computer: they can affect PCs or Apple Macintoshes. It can be spread by Word files sent in e-mail, or on floppy discs.
Such viruses are only possible because Microsoft has increasingly made Word less like a replacement for the typewriter, and more a programmers' tool, which can carry out independent instructions such as opening files or writing words without the user's intervention. Millions of copies are used worldwide, but most people use only a fraction of the program's capability.
"To consider taking out the functionality [that makes macro viruses feasible] would be a step back for the industry," said Stuart Anderson, Microsoft UK's support services manager. "I mean, can you have too much functionality?"Reuse content