From ciac@tholia.llnl.gov Fri Jan 23 17:30:47 1998 From: CIAC Mail User To: ciac-bulletin@tholia.llnl.gov Date: Thu, 22 Jan 1998 13:22:34 -0800 (PST) Subject: CIAC Bulletin I-024: CGI Security Hole in EWS1.1 Vulnerability [ For Public Release ] -----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN CGI Security Hole in EWS1.1 Vulnerability January 21, 1998 18:00 GMT Number I-024 ______________________________________________________________________________ PROBLEM: A vulnerability exsists in EWS1.1 (Excite for Web Servers, version 1.1). PLATFORM: Unix and Windows NT DAMAGE: If exploited, an unauthorized user may execute shell commands on the host system. SOLUTION: Apply the latest patches or workaround listed in Section III. ______________________________________________________________________________ VULNERABILITY Excite, Inc. urges you to act on this information as soon as ASSESSMENT: possible. ______________________________________________________________________________ [ Start CERT Advisory ] ============================================================================= CERT* Vendor-Initiated Bulletin VB-98.01 Jan. 16, 1998 Issue Date: Jan. 19, 1998 Topic: CGI Security Hole in EWS1.1 Source: Excite, Inc. To aid in the wide distribution of essential security information, the CERT Coordination Center is forwarding the following information from Excite, Inc. Excite, Inc. urges you to act on this information as soon as possible. Excite, Inc. contact information is included in the forwarded text below; please contact them if you have any questions or need further information. =======================FORWARDED TEXT STARTS HERE============================ Topic: CGI Security Hole in EWS1.1 Source: Excite, Inc. 555 Broadway, Redwood City, CA 94063 http://www.excite.com Problem: Vulnerability in EWS1.1, Unix and Windows NT platforms I. Description Excite for Web Servers, version 1.1, for Unix and Windows NT platforms, contains a security hole that could allow a malicious user of the software to execute shell commands on the the host system on which EWS has been installed. In situations where the web server is running under a user-id with sufficient access privileges, a hacker could conceivably cause damage to the host system. EWS's search CGI is implemented in Perl and invokes a binary program to actually perform the search against the corpus. The function of the Perl CGI is to parse the results from the search engine and render them in HTML. This bug in no way affects Excite.com, anyone visiting or searching Excite.com, any search boxes (for example, those on the Netscape and Microsoft sites) that point to Excite.com, or sites that the Excite spider indexes. II. Impact Because a search entered by a user into the web page is passed as command line argument to the search binary, and because the command line is interpreted by the shell before the search binary is invoked, it is possible for a hacker with sufficient know-how to craft a search that could cause commands embedded in the search string to be invoked on the host system. III. Solution IMPORTANT: Please note that if you have obtained patches from Excite or a third party site prior to 1/16/98, you do not have the most recent version of the patch. Please visit the patches page referenced below to obtain the latest vresion of the patches, which have evaluated and tested internally, as well as by CERT (http://www.cert.org). The security hole can be corrected by replacing single Perl library file that is part of the EWS1.1 distribution. There are two new versions of this file available at http://www.excite.com/navigate/patches.html. One version is for Unix platforms, the other is for Windows NT platforms. Changes are confined to two subroutines within the architext_query.pl library file. The subroutines in question are 'MakeQuery' and 'MakeGather'. To apply the patch, simply replace the file architext_query.pl, which appears in the 'perllib' subdirectory of the EWS installation, with one of the files posted at the URL provided above. Note that comments at the top of the file indicate which operating system it is intended for, either Unix platforms, or Windows NT platforms. For Unix platforms, the changes made to these routines invoke the search binaries using Perl's 'exec', which calls C's execvp(3), thus bypassing any shell processing of the command. By avoiding shell processing of the command, the security hole is closed and prevents any attacks using shell-based hacking. It is not possible to use the same solution in the Windows NT implementation of Perl, so the patch for Windows NT takes a different approach, by defining a set of legal characters for a search string, and then 'sanitizing' the string by removing any characters that are not members of the set of legal characters. For more information, please visit http://www.excite.com/navigate. ========================FORWARDED TEXT ENDS HERE============================= [ End CERT Advisory ] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of CERT for the information contained in this bulletin. ______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 510-422-8193 FAX: +1 510-423-8002 STU-III: +1 510-423-2604 E-mail: ciac@llnl.gov For emergencies and off-hour assistance, DOE, DOE contractor sites, and the NIH may contact CIAC 24-hours a day. During off hours (5PM - 8AM PST), call the CIAC voice number 510-422-8193 and leave a message, or call 800-759-7243 (800-SKY-PAGE) to send a Sky Page. CIAC has two Sky Page PIN numbers, the primary PIN number, 8550070, is for the CIAC duty person, and the secondary PIN number, 8550074 is for the CIAC Project Leader. Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ (or http://ciac.llnl.gov -- they're the same machine) Anonymous FTP: ftp.ciac.org (or ciac.llnl.gov -- they're the same machine) Modem access: +1 (510) 423-4753 (28.8K baud) +1 (510) 423-3331 (28.8K baud) CIAC has several self-subscribing mailing lists for electronic publications: 1. CIAC-BULLETIN for Advisories, highest priority - time critical information and Bulletins, important computer security information; 2. SPI-ANNOUNCE for official news about Security Profile Inspector (SPI) software updates, new features, distribution and availability; 3. SPI-NOTES, for discussion of problems and solutions regarding the use of SPI products. Our mailing lists are managed by a public domain software package called Majordomo, which ignores E-mail header subject lines. To subscribe (add yourself) to one of our mailing lists, send the following request as the E-mail message body, substituting ciac-bulletin, spi-announce OR spi-notes for list-name: E-mail to ciac-listproc@llnl.gov or majordomo@tholia.llnl.gov: subscribe list-name e.g., subscribe ciac-bulletin You will receive an acknowledgment email immediately with a confirmation that you will need to mail back to the addresses above, as per the instructions in the email. This is a partial protection to make sure you are really the one who asked to be signed up for the list in question. If you include the word 'help' in the body of an email to the above address, it will also send back an information file on how to subscribe/unsubscribe, get past issues of CIAC bulletins via email, etc. PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC) I-014: Vulnerability in GlimpseHTTP and WebGlimpse cgi-bin Packages I-015: SGI IRIX Vulnerabilities (syserr and permissions programs) I-016: SCO /usr/bin/X11/scoterm Vulnerability I-017: statd Buffer Overrun Vulnerability I-018: FTP Bounce Vulnerability I-019: Tools Generating IP Denial-of-Service Attacks I-020: Cisco 7xx password buffer overflow - DOS I-021: "smurf" IP Denial-of-Service Attacks I-022: IBM AIX "routed" daemon Vulnerability -----BEGIN PGP SIGNATURE----- Version: 4.0 Business Edition iQCVAwUBNMZoprnzJzdsy3QZAQG7awP+Oz1OV0ULVcGK2LlZc4/MRs1wyTRPj38Y 3n4QkKOv8SEZqeNLeDdGxbjrHvl42idU/E6UO7NzxbXU1lx2g+GCy0EBIaIYMrE+ REzY9UdgrXrMvUy5+u7eyAmXrslESMSltAW4U+9r6vKCQK0aYgetugu1/D5qNpyv f/VzP3zjKiE= =Z8VS -----END PGP SIGNATURE-----