nasty ones. Micro$oft has some information on it including how to prevent it from coming back in the future. the W32.Chir.B@mm is a network-aware, mass-mailing worm. It is also a file-infector virus. W32.Chir.B@mm is a variant of W32.Chir@mm. W32.Chir.B@mm uses its own Simple Mail Transfer Protocol (SMTP) engine to send itself to all of the e-mail addresses that it finds in the Windows Address Book (.wab file), and in .adc, r.db, .doc, and .xls files.
http://support.microsoft.com/?scid=kb;en-us;327203