Virus.DOS.33.525 is a memory resident parasitic virus on DOS.


When the virus is loaded into memory, it hooks INT 21h to infect any DOS executable that is run or accessed by writing itself to the end of the file.

On infecting a file, it also places the number of the generation into its binary.

Advanced details

The TSR memory usage of the virus is 1,024 bytes.

MD5 hash:



When the current generation is 4, the virus would activate by resetting the computer when a DOS program is run, however this file would not be infected.

If the first infected file to be run is the 4th generation, the virus would assume that the current generation is also 4 after loading into memory and would trigger when the user runs a DOS program afterwards.

Other details

The virus contains the internal text string: