Yet again another virus has been created. Bagle.B is beginning to appear in increasing numbers and is like many of the more recent viruses, harvesting addresses from the Outlook e-mail program and then sending messages via its own e-mail engine.
This virus also installs a backdoor in any machines infected that can have some remote control over compromised PC's.
Bagle.B is much like its predecessor that was released in January of this year and is activated when the user opens the attachment on the e-mail. Source