This virus comes through e-mail as an attached file, with the body of the mail apparently empty but which actually contains the code to use an exploit which will execute the virus when the user just view the message (if he is using Outlook or Outlook Express without latest Service Packs or patches from Microsoft). Once installed it copies itself in the system directory with the nameriched20.dll modifying itself to be loaded as a DLL. This DLL is used by applications that work with Richedit Text Format such as Wordpad.
