Full Disclosure mailing list archives
Re: linksys WRT54g authentication bypass
From: "Shawn Merdinger" <shawnmer () gmail com>
Date: Fri, 4 Aug 2006 13:35:56 -0700
Nice find. But probably not a big deal since these are just home-use routers, right? Well, maybe not. 1. Sandia nuclear plant scada network recommended gear doc (October, 2005): http://www.sandia.gov/scada/documents/NSTB_NSIT_V1_2.pdf You'll see when you read the doc that the crux of the testing was to get the SCADA protocols through a couple of PIXs...that didn't work b/c of NAT problems, so they threw in a couple Linksys routers to handle the NAT. OK, so a PIX and Linksys scada deployment is bad, right? Well it gets worse. Look on page 6 of the PDF and you'll see this: "The Pix firewalls were upgraded to the latest PixOS (6.3). They were not identical in that one had a crypto card and license while the other was in a stock configuration. The two Linksys firewalls were a BEFVP41 v1 with firmware version 1.41.1 and a BEFVP41 v2 with firmware version 1.01.04." Both of those versions of Linksys router software had known, published vulnerabilities at the time this document was published. http://nvd.nist.gov/nvd.cfm?cvename=CVE-2002-0426 http://nvd.nist.gov/nvd.cfm?cvename=CVE-2002-1312 2. EPA Water and Wastewater Security Product Guide located at http://cfpub.epa.gov/safewater/watersecurity/guide/productguide.cfm?page=wirelessdatacommunications This EPA "Water and Wastewater Security Product Guide" has a picture of a Linksys WRT54G AP on the page. The network diagram illustrates the Linksys AP connected directly into the SCADA management network. At the bottom of the page you'll see the following statement: "Cost The cost of a wireless LAN using 802.11 can be under $50 each for a WAP and a wireless card. A small system can be securely set up in a few hours by a knowledgeable computer technician." Gee, didn't the EPA get GAO's "A+" rating in the CyberSecurity Report Card? Perhaps they got the "A+" because they simply have a product security guide webpage? 3. California Energy Commission report "Focus II Monitoring Final Report" mentions a Linksys router used in monitoring operations – see appendix, page E-3. http://www.energy.ca.gov/2005publications/CEC-500-2005-009/CEC-500-05-009.PDF There's plenty more...left as an exercise to the reader. Btw, can anyone here find on Linksys.com a list of product vulns and fixes? Thanks, --scm On 8/4/06, Ginsu Rabbit <ginsurabbit () hotmail com> wrote:
I'm having some trouble believing this hasn't been reported before. If you have a linksys router handy, please check to see whether it is vulnerable to this attack. It's possible that all of the linksys router web UIs have the same bug. Hopefully the problem is isolated to one particular model or firmware revision. I. DESCRIPTION Tested product: Linksys WRT54g home router, firmware revision 1.00.9. Problem #1: No password validation for configuration settings. The WRT54g does not attempt to verify a username and password when configuration settings are being changed. If you wish to read configuration settings, you must provide the administrator ID and password via HTTP basic authentication. No similar check is done for configuration changes. This request results in a user-id and password prompt: GET /wireless.htm This request disables wireless security on the router, with no password prompt: POST /Security.tri Content-Length: 24 SecurityMode=0&layout=en Problem #2: Cross-site request forgery The web administration console does not verify that the request to change the router configuration is being made with the consent of the administrator. Any web site can force a browser to send a request to the linksys router, and the router will accept the request. II. Exploitation The combination of these two bugs means that any internet web site can change the configuration of your router. Recently published techniques for port-scanning and web server finger printing via java and javascript make this even easier. The attack scenario is as follows: - intranet user visits a malicious web site - malicious web site returns specially crafted HTML page - intranet user's browser automatically sends a request to the router that enables the remote administration interface - the owner of the malicious web site now has complete access to your router I'm not going to share the "specially crafted HTML page" at this time, but it isn't all that special. III. DETECTION If your router is vulnerable, the following curl command will disable wireless security on your router. Tests for other router models and firmware revisions may be different: curl -d "SecurityMode=0&layout=en" http://192.168.0.1/Security.tri IV. MITIGATION 1) Make sure you've disabled the remote administration feature of your router. If you have this "feature" enabled, anybody on the internet can take control of the router. 2) Change the IP address of the router to a random value, preferably in the range assigned to private networks. For example, change the IP address to 10.x.y.z, where x, y, and z are numbers between 0 and 255 inclusive. This makes it more difficult for an attacker to forge the request necessary to change the router configuration. This mitigation technique might not help much if you have a java-enabled browser, because of recently published techniques for determining gateway addresses via java applets. 3) Disable HTTP access to the administration interface of the router, allowing only HTTPS access. Under most circumstances, this will cause the browser to show a certificate warning before the configuration is changed. V. VENDOR NOTIFICATION Linksys customer support was notified on June 24, 2006. Full disclosure on August 4, 2006. -- GR _________________________________________________________________ Is your PC infected? Get a FREE online computer virus scan from McAfee(r) Security. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
_______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Current thread:
- linksys WRT54g authentication bypass Ginsu Rabbit (Aug 04)
- Re: linksys WRT54g authentication bypass Shawn Merdinger (Aug 04)