Kriz.4029 is a resident and polymorphic virus that activates on December 25, but only in computers with the program SoftIce installed.
Kriz.4029 prevents the computer from starting up, as it deletes the content of the CMOS memory.
In addition, Kriz.4029 renders files in all disk drives unusable, as it overwrites them, and deletes the content of the Flash BIOS.
Kriz.4029 does not spread automatically using its own means. It needs the attacking user's intervention in order to reach the affected computer. The means of transmission used include, among others, floppy disks, CD-ROMs, e-mail messages with attached files, Internet downloads, FTP, IRC channels, peer-to-peer (P2P) file sharing networks, etc.