Dell TrueMobile 2300 Wireless Broadband Router Authentication Bypass Vulnerability iDefense Security Advisory 12.07.05 www.idefense.com/application/poi/display?id=348&type=vulnerabilities December 7, 2005 I. BACKGROUND The Dell TrueMobile 2300 Wireless Broadband Router is an 802.11b/g wireless access point, wired ethernet switch and internet router. More information can be found at the following URL: http://support.dell.com/support/edocs/network/p57205/en/intro/index.htm II. DESCRIPTION Remote exploitation of a design error in Dell Inc.'s TrueMobile 2300 Wireless Router may allow an attacker to reset the authentication credentials. The Dell TrueMobile 2300 is a wireless router and access point. By requesting the following url from the router, it is possible to obtain a page containing a form which allows you to reset the authentication credentials. (The IP is typically 192.168.2.1, and [ROUTER IP] should be replace by the router's actual address.) http://[ROUTER IP]/apply.cgi?Page=adv_password.asp&action=ClearLog Although dialog boxes for entering the username and password appear, pressing cancel will not prevent this exploit from working. III. ANALYSIS Exploitation could allow remote attackers to associate with the internal side of the router to change any configuration settings, including uploading of new firmware. The precise cause of the error is unknown. Although there is GPL source code available for this product, the firmware's source code version has not been kept up to date with the binary version. As a result, it does not directly allow the cause of the vulnerability to be determined. Based on analysis of the affected binary, /usr/sbin/httpd, and the previous version of the source code it appears the cause is a logic error involving the 'ClearLog' string being checked without first ascertaining that the page was one where that made sense. Although the binary appears to be largely the same code as the available source code, there are many differences. In the binary version, the authentication is not performed in the same order as in the source version. It is likely that the determination of which pages to check is now done on the basis of the 'action' variable, rather than the previous method of using the page name. IV. DETECTION iDefense has confirmed the existence of this vulnerability in the following Dell TrueMobile 2300 firmware versions: ? 3.0.0.8, dated 07/24/2003 ? 5.1.1.6, dated 1/31/2004 Previous versions of this may also be affected, however it is not clear in which version the vulnerability was introduced. V. WORKAROUND In order to mitigate exposure to this vulnerability from remote attackers, employ encryption on your wireless interface, or disable it if it is not required. The exact settings to use are dependant on your wireless security policy. This workaround does not prevent exploitation from the local network via wired interfaces. VI. VENDOR RESPONSE "The vendor is no longer selling this product and has replaced it with newer models that do not exhibit the defect. Therefore, a patch will not be released to address this issue." VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2005-3661 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 11/17/2005 Initial vendor notification 11/18/2005 Initial vendor response 12/07/2005 Public disclosure IX. CREDIT TNull is credited with the discovery of this vulnerability. Get paid for vulnerability research http://www.iDefense.com/poi/teams/vcp.jsp Free tools, research and upcoming events http://labs.iDefense.com X. LEGAL NOTICES Copyright © 2005 iDefense, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDefense. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please email customerservice (at) iDefense (dot) com [email concealed] for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.