Cuerpo is an email worm that propagates by using the Outlook address book of infected systems. The worm infects computers that are running Windows 9x, with Internet Explorer 5.0 installed without the Scriptlet.TypeLib hotfix. The email, in HTML format, is blank, bar from script that allows the worm to execute. Upon opening the email, the user may receive an ActiveX notification. Upon clicking an option, the worm will execute. The worm will attempt to collect email addresses from the infected computer, in order to spread further.