Lunedo.b is a macro virus that infects Microsoft Word documents and disables Microsoft Word security functions. It also lowers Internet Explorer security settings, disables the Windows Security Center, the Task Manager and the Registry Editor. Furthermore, Lunedo.b can turn off the System Restore, alter Windows Firewall settings, delete some standard Windows tools and vital components of Microsoft Office and MSN software. The worm may also display certain messages, repeatedly open and close the CD-ROM tray.