-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Vulnerability in GlimpseHTTP and WebGlimpse cgi-bin Packages November 14, 1997 22:00 GMT Number I-014 ______________________________________________________________________________ PROBLEM: Vulnerabilities have been identified in GlimpseHTTP and WebGlimpse using the cgi-bin programs in these packages. PLATFORM: GlimpseHTTP 2.0 (and prior) WebGlimpse (prior to 1.5) DAMAGE: If exploited, remote users may be able to execute arbitrary commands with the privileges of the httpd process which answers HTTP requests. SOLUTION: Apply workarounds listed below in Section 3. ______________________________________________________________________________ VULNERABILITY Reports have been received of intruders exploiting these ASSESSMENT: vulnerabilities. It is recommended that sites that have either of these packages installed take the steps outlined in Section 3 as soon as possible. ______________________________________________________________________________ [ Start AUSCERT Advisory ] =========================================================================== AA-97.28 AUSCERT Advisory Vulnerability in GlimpseHTTP and WebGlimpse cgi-bin Packages 14 November 1997 Last Revised: -- - ---------------------------------------------------------------------------- The Australian Computer Emergency Response Team (AUSCERT) has received information about vulnerabilities in the GlimpseHTTP and WebGlimpse cgi-bin packages. AUSCERT is currently receiving reports of intruders exploiting these vulnerabilities. AUSCERT recommends that sites that have either of these packages installed take the steps outlined in Section 3 as soon as possible. - ---------------------------------------------------------------------------- 1. Description AUSCERT has received information that vulnerabilities exist in the GlimpseHTTP and WebGlimpse packages. Both of these packages provide a web interface which allows you to use Glimpse, an indexing and query system, to provide a search facility for your web site. The cgi-bin programs in these packages perform insufficient argument checking. Due to this, intruders may be able to execute arbitrary commands with the privileges of the httpd process. GlimpseHTTP 2.0 is known to be vulnerable in this fashion. The authors of GlimpseHTTP and WebGlimpse also believe earlier versions of both GlimpseHTTP (prior to 2.0) and WebGlimpse (prior to 1.5) may be vulnerable to similar attacks. WebGlimpse version 1.5 addresses the vulnerabilities in both of these packages. In particular, AUSCERT is receiving reports of attacks using the aglimpse cgi-bin program (part of GlimpseHTTP). To check whether exploitation of the GlimpseHTTP vulnerability has been attempted against your site, search for accesses to the aglimpse program in your access logs. An example of how to do this is: # egrep -i 'aglimpse.*(\||IFS)' {WWW_HOME}/logs/access_log Where {WWW_HOME} is the base directory for your web server. If this command returns anything, further investigation is necessary. Both GlimpseHTTP and WebGlimpse are commonly used packages and sites are encouraged to check for aglimpse (part of GlimpseHTTP) and webglimpse (part of WebGlimpse). If either GlimpseHTTP or WebGlimpse is installed it is recommended that the workarounds given in section 3 are applied. Up-to-date information regarding this vulnerability has been made available by the authors of GlimpseHTTP and WebGlimpse. It is available from: http://glimpse.cs.arizona.edu/security.html 2. Impact Remote users may be able to execute arbitrary commands with the privileges of the httpd process which answers HTTP requests. This may be used to compromise the http server and under certain configurations gain privileged access. 3. Workarounds/Solution GlimpseHTTP 2.0 is known to be affected by the vulnerability described in this advisory. The authors of GlimpseHTTP and WebGlimpse also believe earlier versions of both GlimpseHTTP (prior to 2.0) and WebGlimpse (prior to 1.5) should be considered vulnerable to similar attacks. Information on removing the GlimpseHTTP and WebGlimpse vulnerabilities described in this advisory may be found in Sections 3.2 and 3.3. Until these packages can be upgraded it is advised that the functionality provided by these packages be disabled (Section 3.1). 3.1 Remove execute permissions To prevent the exploitation of the vulnerabilities described in this advisory, AUSCERT recommends that the execute permissions for all cgi-bin programs associated with GlimpseHTTP and WebGlimpse be removed. Note that this will have the side effect of preventing the search facilities provided by these packages from functioning. 3.2 Replacing GlimpseHTTP with WebGlimpse GlimpseHTTP is no longer supported and its authors recommend that sites replace it with the current version of the WebGlimpse package (see Section 3.3). Sites should ensure that all programs related to GlimpseHTTP are removed or disabled prior to installing the WebGlimpse package. 3.3 Upgrading to the current version of WebGlimpse A new version of WebGlimpse has been released which addresses the vulnerabilities described in this advisory. Sites using WebGlimpse should upgrade to the current version, which at the moment is 1.5 (released on 13 November 1997). It can be retrieved from: ftp://ftp.cs.arizona.edu/glimpse/webglimpse-1.5.src.tar.gz More information on WebGlimpse may be found at: http://glimpse.cs.arizona.edu/webglimpse/ 4. Additional measures It is important to note that attacks similar to this may succeed against any CGI program which has not been written with due consideration for security. Sites using HTTP servers, and in particular CGI applications, are encouraged to develop an understanding of the security issues involved. Sites should consider taking this opportunity to examine their httpd configuration and web servers. In particular, all CGI programs that are not required should be removed, and all those remaining should be examined for possible security vulnerabilities. It is also important to ensure that all child processes of httpd are running as a non-privileged user. This is often a configurable option. See the documentation for your httpd distribution for more details. Numerous resources relating to WWW security are available. The following pages may provide a useful starting point. They include links describing general WWW security, secure httpd setup and secure CGI programming. W3C Security Resources (including WWW Security FAQ): http://www.w3.org/Security/ NSCA's "Security Concerns on the Web" Page: http://hoohoo.ncsa.uiuc.edu/security-1.0/ The following books contain useful information on Web security including sections on secure programming techniques. "Web Security Sourcebook", Aviel Rubin, Daniel Geer and Marcus Ranum, John Wiley & Sons, Inc., 1997. "Web Security & Commerce", Simson Garfinkel with Gene Spafford, O'Reilly and Associates, 1997. CERT/CC have also produced a document describing how to sanitise user-supplied data to cgi-bin programs. This can be retreived from: ftp://ftp.cert.org/pub/tech_tips/cgi_metacharacters ftp://ftp.auscert.org.au/pub/cert/tech_tips/cgi_metacharacters Please note that the URLs and books referenced in this advisory are not under AUSCERT's control and therefore AUSCERT cannot be responsible for their availability or content. - ---------------------------------------------------------------------------- AUSCERT thanks Udi Manber and CERT/CC for their assistance in the preparation of this advisory. Thanks also to Stephane Bortzmeyer for the initial report to the authors of GlimpseHTTP. - ---------------------------------------------------------------------------- The AUSCERT team have made every effort to ensure that the information contained in this document is accurate. However, the decision to use the information described is the responsibility of each user or organisation. The appropriateness of this document for an organisation or individual system should be considered before application in conjunction with local policies and procedures. AUSCERT takes no responsibility for the consequences of applying the contents of this document. If you believe that your system has been compromised, contact AUSCERT or your representative in FIRST (Forum of Incident Response and Security Teams). AUSCERT is located at The University of Queensland within the Prentice Centre. AUSCERT is a full member of the Forum of Incident Response and Security Teams (FIRST). AUSCERT maintains an anonymous FTP service which is found on: ftp://ftp.auscert.org.au/pub/. This archive contains past SERT and AUSCERT Advisories, and other computer security information. AUSCERT also maintains a World Wide Web service which is found on: http://www.auscert.org.au/. Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 4477 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AUSCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. Postal: Australian Computer Emergency Response Team Prentice Centre The University of Queensland Brisbane Qld. 4072. AUSTRALIA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Revision History ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [ End AUSCERT Advisory ] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of AUSCERT 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://ciac.llnl.gov/ Anonymous FTP: ciac.llnl.gov (198.128.39.53) 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-bulletins 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-003: HP-UX mediainit(1) Vulnerability I-004: NEC/UNIX "nosuid" mount option Vulnerability I-006: IBM AIX "xdat" Buffer Overflow Vulnerability I-007: SunOS Solaris Vulnerabilies (nis_cachemgr, ftpd/rlogind, sysdef) I-008: Open Group OSF/DCE Denial-of-Service Vulnerability I-009: IBM AIX libDtSvc.a Buffer Overflow Vulnerability I-010: HP-UX CDE Vulnerability I-011: IBM AIX portmir command Vulnerability I-012: IBM AIX ftp client Vulnerability I-013: Count.cgi Buffer Overrun Vulnerabiliity -----BEGIN PGP SIGNATURE----- Version: 4.0 Business Edition iQCVAwUBNHDUqLnzJzdsy3QZAQFz3AQAqsMwl8bJM/aT6nwjMi58wckwxoxbJTOE d/ukecgCmX38kbu0Z6lwulAduLM0+xLQrqmlTE0VGyjoXfYcEjWV74sMksDmjOoI 2Mk5MBLmz1g/jXXX/+/oxa7ehicUB2mewNJTnE0UQJt+yYsCN6C6gi8ERUBP33jb TpWb2BkaIl8= =gWqq -----END PGP SIGNATURE-----