WebApp Sec mailing list archives
Re: Preventing direct URL access in a J2EE environment
From: Kevin Conaway <kevin.conaway () gmail com>
Date: Wed, 2 Mar 2005 07:54:48 -0500
Blocking the referrer does nothing for me in this context. A.) You should NEVER rely on input from the user do to security validations and B.) I cant use the referrer tag since it will show up as coming from my site when users are browsing legitimately. I just want to enforce that users actually click on a link to go to a certain page, not type in the URL manually. Thanks Kevin On Tue, 1 Mar 2005 21:22:52 -0800, Saqib Ali <docbook.xml () gmail com> wrote:
well for most applications that require anti-leeching, just deny any HTTP request which has the HTTP_REFERER set to blank. In Peace, Saqib Ali http://validate.sf.net On Tue, 1 Mar 2005 14:34:30 -0800 (PST), RSnake <rsnake () shocking com> wrote:Referers are also not availible in some security settings. Zonelabs Zone Alarm Pro, and both Norton Internet Security and Norton Personal Firewall all drop the referring URL. Forget spoofable, sometimes it's just not there at all. See this for details from Symantec: http://service1.symantec.com/SUPPORT/nip.nsf/46f26a2d6dafb0a788256bc7005c3fa3/b9b47ad7eddd343b88256c6b006a85a8?OpenDocument&src=bar_sch_nam There are a number of tricks you can use to get more information from the user's machine, but Referring URL isn't reliable. Not to mention it can also be non-existant via meta refreshing. On Tue, 1 Mar 2005, Saqib Ali wrote:It is a commonly used technique called anti-leeching or anti-leaching . Search for "anti leeching php" or "anti leeching jsp" on Google. You will find many resources. You can control the path that a user takes by checking for the HTTP_REFERER . But this is not a fail-proof technique, because the HTTP_REFERER can alwasy be spoofed. In Peace, Saqib Ali http://validate.sf.net On Tue, 1 Mar 2005 10:19:37 -0500, Kevin Conaway <kevin.conaway () gmail com> wrote:For our application, we would like to prevent users from requesting application resources directly. E.g. browsing to http://localhost/app/method.do?id=5&type=3 instead of actually clicking on a link that the application provides. We would like to do this without a major impact on our code. I was thinking of using the following scenario: - Currently we have tag libraries that help build all our URLS. These tag libraries would be modified to include a strong cryptographic token that is unique to each URL/User combination. - The token/URL combination would be stored in the application context for a pre-determined amount of time. - Next, we would use a Servlet filter to intercept the URL. First, deny URLS requested without tokens. If a token is passed, verify that matches the token stored in the application context for the requested URL. For the token, I was considering using SecureRandom to generate a random number and compute a hash of the random number and the URI being requested. This would be stored along with with URI and the user Id. Could anyone point out any pitfalls I need to be aware of, or if I'm going about things the wrong way? Thanks Kevin-- In Peace, Saqib Ali http://tools.tldp.org/search.php <--- Search for Linux HOWTOs-R XSS Cheatsheet: http://www.shocking.com/~rsnake/xss.html The information in this email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it is expressly prohibited and may be unlawful.-- In Peace, Saqib Ali http://tools.tldp.org/search.php <--- Search for Linux HOWTOs
Current thread:
- Preventing direct URL access in a J2EE environment Kevin Conaway (Mar 01)
- Re: Preventing direct URL access in a J2EE environment Saqib Ali (Mar 01)
- Re: Preventing direct URL access in a J2EE environment RSnake (Mar 03)
- Re: Preventing direct URL access in a J2EE environment Saqib Ali (Mar 03)
- Re: Preventing direct URL access in a J2EE environment Kevin Conaway (Mar 03)
- Re: Preventing direct URL access in a J2EE environment Dwayne Ghant (Mar 03)
- RE: Preventing direct URL access in a J2EE environment David Robert (Mar 06)
- Re: Preventing direct URL access in a J2EE environment Kevin Conaway (Mar 06)
- Re: Preventing direct URL access in a J2EE environment Paul Johnston (Mar 13)
- Re: Preventing direct URL access in a J2EE environment RSnake (Mar 03)
- Re: Preventing direct URL access in a J2EE environment Jeroen van Rijn (Mar 03)
- Re: Preventing direct URL access in a J2EE environment Roy Britten (Mar 03)
- Re: Preventing direct URL access in a J2EE environment Saqib Ali (Mar 01)
- Re: Preventing direct URL access in a J2EE environment Jeroen van Rijn (Mar 03)
- <Possible follow-ups>
- RE: Preventing direct URL access in a J2EE environment Jeff Robertson (Mar 03)
- RE: Preventing direct URL access in a J2EE environment Scovetta, Michael V (Mar 03)