“A new Internet worm that spread through Asia, Australia and Europe on Monday is expected to take hold in the United States on Tuesday as people go back to work after the Martin Luther King Jr. holiday. The ‘Bagle’ or ‘Beagle’ worm arrives as an attachment to an e-mail with the subject line ‘Hi’ and ‘test : )’ in the body text. The worm is activated when a user clicks on the attached file,” Brian Krebs reports for The Washington Post.

“Once the attachment is opened, the worm tries to send copies of itself to all of the e-mail addresses that it finds on the victim’s computer, faking the return address with one randomly generated from those sifted from the infected PC. It also installs a program that lets attackers connect to infected machines, install malicious software or steal files,” Krebs reports. “The worm probably is the precursor to more evolved versions that could wreak havoc with small business and home Internet users, computer security experts said.”

“Carey Nachenberg, chief architect of Symantec Research Labs in Cupertino, Calif., said he expects the worm to continue its rapid spread as more Americans begin sorting through the e-mail that piled up in their in-boxes following the three-day weekend,” Krebs reports. ‘This is coming on hard and fast, and that’s usually a bad sign going into a shortened work week,’ Nachenberg said. Bagle has spread to computers in more than 100 countries, according to MessageLabs, an e-mail security company in New York City.”

Macintosh users are unaffected.

Full article here.