• This is a polymorphic virus that infects COM and DOS EXE files.

  • When an infected file is executed, the virus stays resident in memory by hooking Interrupt 21h.

  • The infection routine is triggered through various actions by the user, such as the following:
    • setting the current directory
    • creating a file
    • opening an existing file
    • deleting a file
    • getting/setting file attributes
    • renaming a file
    • executing a program

  • It appends its code to target host files.

  • The virus contains the following text strings:
    • Freddy KRueGer 2.1
    • Hi Fridrik!