The FBI launched a hunt Friday for the author of a new computer virus that is sneakier and more destructive than the "Love Bug" that infected millions of machines around the world two weeks ago.
The new virus, called "NewLove," penetrated thousands of computers around the globe Thursday and Friday, causing them to crash.
But it didn't spread with the lightning speed of the Love Bug because many companies employed safeguards put in place against the earlier virus.
"In this perspective, Love Bug was a very positive wake-up call," said Gene Hodges at Network Associates, a software company in Santa Clara, Calif.
The two viruses are similar, and both spread via e-mail. But the Love Bug was recognizable by the words "ILOVEYOU" in the subject line of the e-mail, while NewLove changes subject lines every time it is sent.
NewLove is also more destructive because it erases almost all files on a computer it infects and causes it to crash. The Love Bug targeted only a few files.
Estimates of the damage caused by the Love Bug range up to $10-billion, mostly in lost work time. The NewLove virus is expected to total much less.
Hodges said a company in Israel was the first to report the virus, early Thursday. The company shut down its connection to the Internet to curtail the spread, but the virus later surfaced in Europe and the United States.
This time, U.S. companies were quick to take protective measures.
The subject line of a NewLove e-mail starts with "FW:" and includes the name of a file from the sender's computer. The e-mail will have an attachment with the same name, but it may also have a ".vbs." extension visible.
Clicking on the attachment will activate the virus. Like the Love Bug, NewLove will send itself to everybody in the user's address book.
As with the Love Bug, it will only spread from recipients running Microsoft's Outlook e-mail program. Microsoft said it will release a modification to Outlook to eradicate the virus.