The economic damage wrought by the MyDoom virus is now estimated to stand between $61.8 billion (€48.2 billion) and $75.61 billion (€58.9 billion), according to mi2g, the London-based digital risk analysts.
The damage from the virus, which at one point earlier this month was infecting one in 10 e-mails, dwarfs the effect of last year's Sobig virus, which inflicted between $33.6 billion and $41.1 billion worth of economic damage worldwide.
Last week's announcement by Microsoft, the world's largest software maker, that part of the source code for its Windows operating system was illegally posted on the internet is even more bad news for computer users, and good news for hackers.
Microsoft issued a warning to Windows users that the vulnerability could enable a hacker to gain access to someone else's PC and "take any action on the system, including installing programs, viewing data, changing data, deleting data or creating new accounts with full privileges".
Microsoft issued a "patch" to plug the hole in its software, but the severity of the warning and the long delay between its discovery and the Microsoft announcement has potentially allowed hackers to find flaws in the system.
The company is working with the Federal Bureau of Investigation to find out how its proprietary code was released, Mr Tom Pilla, a Microsoft spokesman, said last week.
Hackers have previously targeted flaws in Microsoft's coding to create viruses, such as the Blaster worm last year, to take control of individual computers and servers.
In November last year, Microsoft announced $5 million in rewards to help capture the creators of malicious software codes - known as malware - after viruses corrupted millions of computers by exploiting the company's programs.
The money includes rewards for tips leading to the arrest of those who unleashed the Blaster worm and the Sobig virus.
The FBI has yet to bring charges against the hackers who unleashed Blaster and SoBig, which shut down US rail services and agencies, as well as phone networks in the Nordic region.
Mi2g warned that predictions that the MyDoom epidemic was scheduled to stop spreading may be premature.
An alert issued by mi2g said that the first variant, MyDoom.a, was programmed to stop spreading last week, but cautioned that the back-door component of the malware has no time limit.
The alert said that MyDoom.a was still running on hundreds of thousands of infected computers, allowing other MyDoom variants and hackers to prowl actively for infected machines.
"Variants of MyDoom and associated malware, such as Deadhat, continue to surface, and more are likely to be in the pipeline based on the trend established in the last two weeks," the mi2g report said.
Last week, a third variant, MyDoom.c, emerged as a stripped-down version of the .a and .b variants. Its sole purpose was to target Microsoft's website with a denial-of-service attack. - (Financial Times Service)
