It is a dangerous memory resident parasitic virus. It does work only under old DOS versions (DOS 3.30 and other), but does not check the DOS version. When an infected file is executed, the virus hooks INT 21h and then writes itself to the end of EXE files that are opened.
The virus corrupts the files with the length greater than 64K. In some cases the virus also corrupts the EXE header fields. While infecting a file the virus patches the INT 24h handler and does not restores it after infection. When infecting a file the virus also displays the 'M' letter to the left top corner on the screen.
