Virus.DOS.Cookie, also referred as Japanese Cookie, is a parasitic virus on DOS.

There are 2 variants:

  • Virus.DOS.Cookie.653
  • Virus.DOS.Cookie.722


When the virus is run, it infects one DOS executable in current directory by random, including COMMAND.COM.

Files larger than 30,720 bytes may be infected incorrectly and could cause a system hang.


The virus randomly activates.

When triggered, it displays the string "Cookie" across the screen with a beep repeatedly, followed by spamming the screen with the text string after a while:

Give me a Cookie

And it waits for the user to input "Cookie" by exact cases. Once detected it stops spamming, displays the message and return to DOS:

Oh Thank you!

Other details

Cookie.722 contains bug that would hang the system on attempting to load into memory.

The virus contains the internal text string:



  1. List of variants of the Japanese Cookie virus on VX Heaven