Denzuko is introduced to a system through infected disks. The virus loads itself into memory when the infected disk is booted. Any disk that is accessed while the virus is in memory will be infected. Even non-bootable disks will be infected, and the viruses contained on those disks will be able to infect if an attempt is made to boot from them.
The virus infects the boot sector as well as 9 sectors on track 40. Typical 360 kilobyte disks only use tracks 0 to 39, so no data will be erased on these disks. On 3.5 inch, 1.2 megabyte and other disks will lose data, as they do use these sectors. It does not infect hard drives. In fact, it stops running if the computer is rebooted from the hard drive.
If the user attempts to reboot the computer with CTRL-ALT-DEL, the words "DEN ZUKO" will appear on the screen with a stylized "O", similar to the AT&T logo. The virus will remain in memory as the computer reboots.
It removes the Brain virus and changes the volume label from "(c) Brain" to "Y.C.1.E.R.P".