WebApp Sec mailing list archives
advice needed - secure transfer of client details
From: Tim James <jimtames () yahoo com>
Date: Fri, 29 Oct 2004 11:18:25 +0100 (BST)
Hi all, This is a brain teaser. I have an application to review which supplies details from the client's workstation (derived from files on disk, hostname, IP address). It currently implements a Java applet whose job is to obtain these details and send them up to the server in an ordinary HTTP POST. This sends alarm bells ringing for me. I have developed a simple attack whereby I can replace the applet at will with my own code, which can send different details for workstation ID, hostname, IP address. This falsifies the audit trail from this point on and the server is none the wiser. So, the general problem is this :- How can a client communicate details that are only known to the client, up to a server, in a way that cannot be tampered with ? Why should a server trust the supplied values ? The data for the workstation next to me is known by everyone - why can't I create an applet to reproduce those details, and hence impersonate that workstation ? I have some ideas but none are totally satisfactory. 1) Encrypt the data This shifts the problem to one of key management. 2) Checksum the applet 3) Keep the details on the server in the first place and supply some token from the client which cannot be impersonated I would *really* appreciate a different perspective on this problem because I'm kind of stalled..... Thanks a lot Tim Send instant messages to your online friends http://uk.messenger.yahoo.com
Current thread:
- advice needed - secure transfer of client details Tim James (Oct 29)
- New Whitepaper - "Second-order Code Injection Attacks" WebAppSecurity [Technicalinfo.net] (Nov 01)
- Re: advice needed - secure transfer of client details Peter Conrad (Nov 01)
- Re: advice needed - secure transfer of client details Ido Rosen (Nov 01)
- Re: advice needed - secure transfer of client details focus (Nov 01)
- Re: advice needed - secure transfer of client details GuidoZ (Nov 01)
- Re: advice needed - secure transfer of client details Alex Russell (Nov 01)
- Re: advice needed - secure transfer of client details Richard Moore (Nov 05)
- <Possible follow-ups>
- RE: advice needed - secure transfer of client details Michael Silk (Nov 01)
- RE: advice needed - secure transfer of client details Scovetta, Michael V (Nov 01)
- RE: advice needed - secure transfer of client details Glenn_Everhart (Nov 05)
(Thread continues...)