This virus infects on file execution all the files that contain 'MZ' in their first two bytes. It pads the infected files to a paragraph boundary, thus adding up to 15 additional bytes of garbage to them.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
Mr. D will not infect files with internal overlay structure. It will also not infect files with "VIR" in their name
After infecting a file, Mr. D attempts to delete a file with the same name and the first character of the extension replaced by '_'. The virus sets the seconds field in the infected files time-stamp to 4.
The virus contains routines to play with the screen and which are activated on 31st of any month, some time after the virus is installed in memory. Mr. D does not spread before March 18, 1993.
The virus contains the string "Mr. D" unencrypted.
There are two variants.