Experts said on Wednesday one reason for the proliferation of computer worms and viruses over the past week was a spat between the authors of at least two of these bugs.

The software firm Sophos said: "A state of war exists between the creators of the Netsky and Bagle worms, both of which have spread widely across the internet in a number of different guises."

Sophos said the latest version of Netsky was designed to remove infections of the Bagle.

Cyber goading

Additionally, the code used for these latest worms contained taunts and insults against the other.

"The two worm authors are goading each other with taunts and malicious code to release more powerful versions of their viruses," said Graham Cluley, senior technology consultant for Sophos.

"We believe both authors may have access to an underground network consisting of thousands of compromised computers owned by innocent users, which are being exploited to launch every new version of their worms."

"Make no mistake, the pranks and spitting contests among the virus writers are becoming increasingly more malicious. Or perhaps 'the big boys' are involved. It seems the latest variants have a more criminal agenda, destroying files and capturing financial information"

Christopher Faulkner,
CI Host web-hosting firm

Christopher Faulkner of the web-hosting firm CI Host said this war was bad news for most computer users and a possible indication of a sinister element within the virus community.

Criminal agenda

"Make no mistake, the pranks and spitting contests among the virus writers are becoming increasingly more malicious," said Faulkner.

"Or perhaps 'the big boys' are involved. It seems the latest variants have a more criminal agenda, destroying files and capturing financial information."

Faulkner said the latest generations of Bagel and Netsky attempt to track down computers infected with the Mydoom worm was an attempt to disable the first virus.

Also, relatively harmless sound files have been imbedded that play audible messages from infected computers.

California-based Panda Software said earlier this week the spread of viruses and their variants "has reached epidemic proportions worldwide".