W97M/Thus.X

Analysis

• Virus consists of one macro module within the class storage
  
• Virus hooks Word event handlers which prevents the opening, creating or closing of infected documents
  
• Virus searches the macro storage of host files for the string

  "'Bethlem'"

  which exists in the virus body, as a means to determine if the host file is already infected

• On March 11th of any year-
  
  • Virus searches for all *.sys files in all subdirectories and attempts to delete them
    
  • Displays a message box of "Happy Birthday"
    
  • Erases all words in the active document and prevents user from using the menu option "Edit | Undo" to recover by resetting Word internal "Undo" list