Some stuff and deadly virus

A new computer virus spread over the Internet yesterday in an apparent attempt to destroy one of its predecessors.

The Netsky.b virus e-mails itself to addresses stored on an infected computer. It also copies itself to folders that appear to be shared with other computers.

Infected e-mail has a file attached that contains the computer code necessary for self-propagation.

"As it replicates itself, the infected machine will become extremely slow because all the bandwidth is being utilized to spread the virus," said Jag Sebbag, general manager of anti-virus software company McAfee Security in Canada.

Netsky.b is a difficult virus to spot because the contents of the e-mail and the name of the attached file can vary wildly. Sometimes the file name for the attachment ends simply with the extension .zip.

Sometimes it has a double extension, such as .rtf.pif.

Once a computer has been infected, the virus tries to deactivate two versions of the Mydoom virus that hit the Internet late last month.

Anti-virus experts have speculated Mydoom was created by supporters of the Linux operating system because it attacked Web sites maintained by Microsoft Corp., a Linux competitor, and the SCO Group. The latter company is involved in an intellectual-property dispute over certain aspects of Linux software.

Sebbag said it's possible someone who supports Microsoft or SCO may have written Netsky.b in retaliation for Mydoom.

McAfee rates the virus as a medium risk threat, largely because of the speed at which it is spreading.

"The infection rate is not what it was with the Mydoom or Sobig virus, where they were spreading at incredible speeds," Sebbag said. "But that may pick up."