Proxy - content filter related

From: Vicky Rode (aptgetd_at_gmail.com)
Date: 06/30/05

  • Next message: Roberts, Scott: "RE: web server chacking." 
    Date: Thu, 30 Jun 2005 11:29:19 -0700
To: security-basics@securityfocus.com

    Hi,

    Looking for some insight regarding dealing with proxy traffic.

    Is it possible to look at the *outgoing* client-proxy request headers
    (w/o going through a local proxy server) in order to identify/block
    proxy related traffic?

    a. users (user-agent) to non-SSL HTTP proxies
    b. users (user-agent) to SLL HTTP proxy (encrypted)

    Since the traffic is being redirected (transparently) via school's
    content filter appliance (open-source product), does it make sense to
    enable proxy so that the appliance provides SSL & non-SSL tunneling
    CONNECT extension method, so that we can identify (via CONNECT) and
    filter traffic (via keyword). Is it a worthwhile effort?

    I can't see any other way to address proxy related traffic (google web
    accelerator as an example) which is currently bypasses our content
    filter based on egress traffic. Unless I perform deep packet inspection,
    look for incoming response, which might slow things down since filtering
    is being done in the software.

    I'm not sure what I can get out of SSL proxy packets since it creates
    a secure connection (encrypted session) between client and server but
    any thoughts will be greatly appreciated.

    The purpose of this is to inspect/block naughty sites which students
    access using third party proxies to bypass school's content filter(s).
    I'm trying to help a public school with this issue and any help will be
    awesome!

    Any pointers to any in-depth papers or books which talks about proxies
    in depth will be excellent.

    Appreciate your time/help.

    regards,
    /vicky

  • Next message: Roberts, Scott: "RE: web server chacking."

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