From xforce@iss.net Thu May 4 10:01:44 2000 From: X-Force Resent-From: mea culpa To: alert@iss.net Resent-To: jericho@attrition.org Date: Wed, 3 May 2000 16:46:46 -0400 (EDT) Subject: ISSalert: Internet Security Systems Security Advisory: Vulnerability in Quake3Arena Auto-Download Feature TO UNSUBSCRIBE: email "unsubscribe alert" in the body of your message to majordomo@iss.net Contact alert-owner@iss.net for help with any problems! --------------------------------------------------------------------------- -----BEGIN PGP SIGNED MESSAGE----- Internet Security Systems Security Advisory May 3, 2000 Vulnerability in Quake3Arena Auto-Download Feature Synopsis: Internet Security Systems (ISS) has identified a vulnerability in id Software's Quake3Arena that could allow an attacker to read or write files on a computer that has the software installed. This vulnerability is important to network administrators who may be unaware that users are accessing potentially malicious Quake3Arena servers outside their network. The environment for Quake3Arena allows client-side modification to read and write files for purposes such as configuration. Modifications run in a protected environment similar to the Java virtual machine but proprietary to id Software. The file access routines in this environment are limited to files installed in the directory where the modification is installed. Modifications are located in subdirectories under the Quake3Arena installation directory. It is possible to open files in directories above the modifications directory allowing an attacker to open any file on the same drive. Combining the ability to access files with the automatic download feature that was added to Quake3Arena in the 1.16 update on March 15, 2000, this vulnerability could be used by an attacker to execute malicious code on any system that connects to a Quake3Arena server. Impact: This vulnerability allows an attacker to have read or write access to a Quake3Arena user's filesystem when the user connects to a server run by the attacker. This could allow attackers to install Trojan horse programs, gather passwords, and read or write files. Affected Versions: Quake3Arena version 1.16 for Windows allows read or write access to files and allows code to be automatically downloaded to the user's system for the purpose of manipulating files. Description: A programming Software Developers Kit (SDK) for Quake3Arena is supplied by id Software along with source code to a major portion of the program logic. The SDK is intended to encourage the development of modifications and enhancements to the program. Within the source code for the client side portion of the program, a number of predefined functions can be called by game modifications. A majority of these functions manipulate data within the game itself and pose no danger to the system on which the software is running. However, four of these functions allow read or write access to the filesystem. The read functions can read files stored on the filesystem as well as data compressed within the PKZIP-compatible .PK3 files. The write functions only write to files directly on the filesystem. Opening files requires a relative path, resulting in access only to files that reside in the subdirectory where the modification has been installed or packed inside the .PK3 files of that directory. The routines used to open files do not remove ".." from file specifications before the file is opened. An attempt to do so will result in the following error message: "WARNING: refusing to create reletive path "C:\etc\etc\etc" The bug in the implementation opens the file despite the above error message. It is possible for the end user of the product to miss the error message since status and error messages are written to the Quake3Arena 'console', which is normally not visible within the program unless the user presses a special key. This bug combined with the automatic downloading feature in version 1.16 could be used to mount an attack. Recommendations: Operators of Quake3Arena servers are not vulnerable to attack. However, before installing a modification and enabling automatic downloading on a server, the server administrator should verify the source of the modification to be sure a Trojan horse program has not been installed. Users of Quake3Arena should disable the auto download feature to prevent this attack. This is done by choosing SETUP from the main menu, followed by GAME OPTIONS. On the list that appears, make sure "Automatic Downloading" is set to OFF. If Automatic Downloading is turned on, you will be warned as files are downloaded to your system. If a user chooses to manually install game modifications to the client, carefully check the modifications for Trojan horse programs. If the modification includes any .QVM files in the package, it could be used to mount an attack as described in this advisory. Any Quake3Arena modification which uses .DLL files should be examined carefully before installation. These modifications do not have the same security safeguards as the virtual environment. Also, be aware that the .PK3 files that are often distributed are PKZIP format files, and could contain within them trojaned .QVM files. Use a PKZIP compatible utility to examine any .PK3 files you receive as part of a Quake3Arena modification. Network administrators who wish to prevent Quake3Arena users from accessing potentially malicious servers outside their network may do so with firewall rules. Quake3Arena servers normally operate on UDP port 27960, but can be configured to run on other port numbers. Since port 27960 is not exclusively registered for the use of Quake3Arena, blocking this port might affect other applications that could arbitrarily choose this port number. Another approach would be to block outbound access to the following specific address from your network via UDP: authorize.quake3arena.com:27952 Currently this address resolves to 192.246.40.56:27952, but it could be spread across multiple IP addresses in the future. This address is used for authentication/copy protection features within Quake3Arena. Clients who cannot send and receive packets to this address over the Internet will not be able to access Internet-based Quake3Arena servers. It is recommended by id Software that all server operators and end users upgrade to the 1.17 point release as soon as possible. The 1.17 point release is available at: http://www.quake3arena.com/ http://www.planetquake.com/ http://www.quake3world.com/ The network protocol was upgraded from prior versions to help facilitate a rapid transition to the new code base. This means that 1.17 will not communicate with prior versions of Quake3Arena. Credits: This vulnerability was researched and discovered by Tim Farley of the ISS X-Force. ISS would like to thank id Software for their response and handling of this vulnerability. _____ About Internet Security Systems (ISS) Internet Security Systems (ISS) is a leading global provider of security management solutions for the Internet. By providing industry-leading SAFEsuite security software, remote managed security services, and strategic consulting and education offerings, ISS is a trusted security provider to its customers, protecting digital assets and ensuring safe and uninterrupted e-business. ISS' security management solutions protect more than 5,500 customers worldwide including 21 of the 25 largest U.S. commercial banks, 10 of the largest telecommunications companies and over 35 government agencies. Founded in 1994, ISS is headquartered in Atlanta, GA, with additional offices throughout North America and international operations in Asia, Australia, Europe, Latin America and the Middle East. For more information, visit the Internet Security Systems web site at www.iss.net or call 888-901-7477. Copyright (c) 2000 Internet Security Systems, Inc. Permission is hereby granted for the redistribution of this Alert electronically. It is not to be edited in any way without express consent of the X-Force. If you wish to reprint the whole or any part of this Alert in any other medium excluding electronic medium, please e-mail xforce@iss.net for permission. Disclaimer The information within this paper may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties with regard to this information. In no event shall the author be liable for any damages whatsoever arising out of or in connection with the use or spread of this information. Any use of this information is at the user's own risk. X-Force PGP Key available at: http://xforce.iss.net/sensitive.php3 as well as on MIT's PGP key server and PGP.com's key server. Please send suggestions, updates, and comments to: X-Force (xforce@iss.net) of Internet Security Systems, Inc. -----BEGIN PGP SIGNATURE----- Version: 2.6.3a Charset: noconv iQCVAwUBORCPpjRfJiV99eG9AQHfywQAptYs3ovR05lKFp2xAJWgwJVo6L6sRkaZ PZbWhLa+UzcTFhgHbSpqEgHJxBR3KKXi4NKPL528vo2Ob3xj673FJlU7UlaBz4iT DAuAMCyI8Vt8eSoYsAQ7M67m0D4a8o5GgICHDwc/WkbdhV3sHK9OEjPi/RQslttv K2vD/q4yv7E= =Ojio -----END PGP SIGNATURE-----