Virus.DOS.Triadi.3998 or Triadi is a virus that runs on MS-DOS.


Triadi is a memory resident parasitic virus. It hooks INT 21h and writes itself in the end of .com and .exe files that are currently executed. The virus is different: the .com files installer uses an opcode that is legal for XT machines only "if the machine is remembered by another device", but a sample of virus was only found in 1998 - 7 years after the virus was made. As a result of this XT-only instruction, the infected .com files halt when executed. After the 10th infection of the virus, the virus manifests itself by a video effect: it switches the computer to video mode, displays an image of 5" floppy disk covered with messages:

Declaration Of Disk Rights

We need REST!!!


(c) 1991, TRIADI

Depending on the system time (at 12:00 PM and at 4:00 PM) the virus displays the messages and waits for "TRD" input:

It's lunch time,

Everybody goes to eat.

Only if you can guess my initial,

I'll let you pass.

It's dinner time,

I want to eat.

I'll let you use the file,

if you can guess my initial.




Virus.DOS.Triadi.3998 by Alles

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