Neko is a memory-resident parasitic polymorphic DOS virus.


It traces INT 13h and 21h, hooks INT 21h and writes itself to the end of .EXE and .COM files, that are executed. On Tuesdays it overwrites files with a program executed displaying:

Hi! My name is Neko[1].
It is a Japan name.
When you see me , please do not worry.
New i am a very kind and cute virus.
I only kill your this file.
But next time i will kill you all.
I will be com back and become fierce.
Neko    version 1.0


There is a variant (Version 2.0) that displays the following message: 

Dear, Mrs.Grandy:
It is me, Neko again! This is the latest version 2.0
Undoubtedly, I am not what I was.
Let me tell you something about my improvement.
I work with the Antilogic Engine I.
It is a new invention. So, Showtime!
Neko    Version 2.0
        Made by Metal Satan

This variant has in infection size of 4894 Bytes. Instead of the original 2518 Bytes.


  1. The term neko is Japanese for "cat".