Bagle and MyDoom back in disguise

Two new mutations of the Bagle and MyDoom worms have been causing havoc this week in Windows computers around the world by attacking younger, less security-conscious computer users.

W32/Bagle-AI forges sender addresses to confuse recipients over the worm's origin. Its subject and message bodies give the impression that the attachment contains pictures, music or information about certain animals.

It can arrive inside a password-protected zip file, where the required password is in the body text, which increases the perception that the email is legitimate.

The W32/MyDoom-N virus attempts to fool the recipients into thinking the message is an automated mail delivery communication.

It opens a backdoor onto the infected machine, allowing authorised users to access the computer remotely without the user's knowledge.

Sean Richmond, the manager of technical support at Sophos Australia and New Zealand said: "With new variants of the Bagle and MyDoom families steadily emerging and infecting computers around the globe, it's vital that businesses keep their anti-virus software updated.

"Unlike humans, anti-virus software is not fooled by social engineering tricks such as duping users into double-clicking dangerous attachments."

Hackers and spammers use the backdoor of an infected machine to turn it into a spam generator, or use it to steal sensitive or financial information about the users.

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