__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Mozilla Firefox Vulnerability [US-CERT Vulnerability Note VU#143297] June 13, 2007 12:00 GMT Number R-274 ______________________________________________________________________________ PROBLEM: Mozilla Firefox allows cross-domain access to an iframe. PLATFORM: Firefox DAMAGE: An attacker may be able to obtain sensitive data from a user, modify the appearance of a webpage or track keystrokes. SOLUTION: There is no practical solution to this problem at the time. Please utilize the workarounds listed in the bulletin below. ______________________________________________________________________________ VULNERABILITY The risk is LOW. An attacker may be able to obtain sensitive ASSESSMENT: data from a user, modify the appearance of a webpage or track keystrokes. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/r-274.shtml ORIGINAL BULLETIN: http://www.kb.cert.org/vuls/id/143297 ______________________________________________________________________________ [***** Start US-CERT Vulnerability Note VU#143297 *****] Vulnerability Note VU#143297 Mozilla Firefox allows cross-domain iframe access via JavaScript Overview Mozilla Firefox allows cross-domain access to an iframe. This vulnerability could allow an attacker to interact with a web site in a different domain. The attacker could read content and cookies, capture keystrokes, and modify content. I. Description An iframe is an HTML element which allows an HTML document to be embedded inside a master HTML document. The Mozilla same origin policy says: The same origin policy prevents document or script loaded from one origin from getting or setting properties of a document from a different origin. The policy dates from Netscape Navigator 2.0. Mozilla considers two pages to have the same origin if the protocol, port (if given), and host are the same for both pages. Firefox does not properly enforce the same origin policy to web pages that use IFrames. From Mozilla Bugzilla Bug ID 382686: The problem you fixed there is that document.write() could be used to overwrite frames that originate from Internet-based SRC= pointing to non-same-domain site. This is fixed and throws a security exception. Unfortunately, the check implemented means that about:blank frames can be overwritten freely; and unfortunately, *all* frames, even with Internet SRC= specified, will be vulnerable to a race condition while the document loads. Note that some websites that allow users to supply content may allow iframes to be included. II. Impact An attacker may be able to obtain sensitive data from a user, modify the appearance of a webpage or track keystrokes. Depending on the nature of the web site the user was visiting, this data may include passwords, credit card numbers, and any arbitrary information provided by the user. III. Solution We are currently unaware of a practical solution to this problem. Workarounds for users Disable JavaScript Use the NoScript Firefox Add-on to whitelist what sites can run JavaScript. Type in URLs directly in the web browser's address bar, or use bookmarks to navigate to websites See the Cross-Site Scripting Vulnerabilities document for general information. Workarounds for administrators Do not allow user submitted content to include JavaScript. Do not allow users to submit content to a shared resource that includes iframes. A shared resource may include the comments section of a blog or a web forum. Monitor the content submitted by third parties for malicious JavaScript or iframes. Systems Affected Vendor Status Date Updated Mozilla Vulnerable 8-Jun-2007 References http://archives.neohapsis.com/archives/fulldisclosure/2007-06/0026.html https://bugzilla.mozilla.org/show_bug.cgi?id=382686 http://www.w3schools.com/tags/tag_iframe.asp http://www.w3.org/TR/html401/present/frames.html#h-16.5 https://addons.mozilla.org/en-US/firefox/addon/722 http://www.mozilla.org/projects/security/components/same-origin.html http://www.cert.org/archive/pdf/cross_site_scripting.pdf http://www.stopbadware.org/home/security#preventing http://www.antiphishing.org/consumer_recs.html Credit This vulnerability was reported by Michal Zalewski on the Full-Disclosure mailing list. This document was written by Ryan Giobbi. Other Information Date Public 06/04/2007 Date First Published 06/08/2007 01:28:14 PM Date Last Updated 06/11/2007 CERT Advisory CVE Name Metric 8.51 Document Revision 22 [***** End US-CERT Vulnerability Note VU#143297 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of US-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: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org 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) R-264: Security Vulnerability in the Authentication Mechanism for Solaris Management Console (SMC) R-265: HP Sysetm Management Homepage (SMH) Vulnerability R-266: Security Vulnerability in How xscreensaver(1) Interacts with GNOME Assistive Technology R-267: Security Notice for CA Products Implementing the Anti-Virus Engine R-268: Vulnerability in Win 32 API (935839) R-269: Cumulative Security Update for Outlook Express and Windows Mail (929123) R-270: Cumulative Security Update for Internet Explorer (933566) R-271: Vulnerability in the Windows Schannel Security Package (935840) R-272: Vulnerabilities in Microsoft Visio (927051) R-273: Vulnerability in Windows Vista (931213)