Mydoom.O worm threat level raised to high

Computer Associates (CA) International today announced that it has raised the threat level for the Mydoom.O worm to high, based on what it calls "extremely intensive activity levels and exponential growth".

Computer users are cautioned to verify any unsolicited emails with senders. Infected Mydoom.O emails may contain one of the following subject lines:

hello

hi

error

status

test

report

delivery failed

Message could not be delivered

Mail System Error - Returned Mail

Delivery reports about your e-mail

Returned mail: see transcript for details

Returned mail: Data format error

Mydoom.O uniquely uses search engines and websites as it seeks to find new targets, and the sheer volume of such traffic effectively causes denial of service attacks.

CA has received more than 1,000 samples today from enterprise customers on Mydoom.O, which is abusing the following sites with intense search activity:

http://search.lycos.com/

http://www.altavista.com/

http://search.yahoo.com/

http://www.google.com/

“Since Mydoom.O can easily spread from PC to PC, it only takes a small number of uninformed victims to start an avalanche of infections,” said Sam Curry, vice president of eTrust security management at CA.

“This underscores the importance of threat awareness and of safe computing practices. We all need to make sure that worms don’t find fertile ground to breed in.”