Re: Tool to find hidden web proxy server

["Balaji Prasad" <bp1974 () comcast net>]

Vinay:
 Couple of options for you ... based on the size and connectivity of your  
network:

Option 1.  (Requires no change to FW policy)
  1. If your LAN is hub based, the skip to step 3. If there is a central  
switch go to step 2.
  2. Most high-end switches have an option for port mirroring. If yours  
has one, then connect a linux box with tcpdump/ethereal/ntop to the  
mirrored port.
  3. If you are using ntop or any other network packet monitoring tool,  
you will notice one or more systems originating a disproportionately  
higher volume of http traffic. Those are your rogue proxy servers

Option 2.(Small change to FW policy)
  Install a policy that does the following:
        a. Your default policy will be to block all traffic out of your network.
	b. Prohibits all traffic to destination:port80 or destination:port443 if  
not originating from your proxy server.
	c. You will need to punch holes in your FW one by one to allow all  
authorized services (SMTP,IMAP,DNS etc.)	
This way you will end up with a more secure installation in general.

Balaji


On Thu, 2 Sep 2004 09:06:44 +0530, vinay mangal <vinay.mangal () eil co in>  
wrote:

> Dear all,
>
> Thanks for your suggestions. May be I am not able to define my question
> properly.
>
> This problem is strictly with in company internet access firewall and in  
> the
> LAN only. In a company, policy for Internet access says it is through IP
> only. The others can not browse the internet. This policy is implemented  
> on
> firewall. Few smart guys have installed free proxy server running on non
> default ports and distributed the internet access to their friends. The
> firewall sees the traffic coming from the authorized IP and does not stop
> them. We want to know who has installed proxy on there machine.
>
> I hope, I am able to clearly define my question. Thanks
>
>
> vinay
>
>
> ----- Original Message -----
> From: "wnorth" <wnorth () verizon net>
> To: "'vinay mangal'" <vinay.mangal () eil co in>; "'Pen'"
> <pen-test () securityfocus com>
> Sent: Wednesday, September 01, 2004 11:41 PM
> Subject: RE: Tool to find hidden web proxy server
>
>
> > I'm not sure of a tool, but simply scanning your network for TCP/8080 or
> > TCP/80 or TCP/8000 may give you the results you are looking for. Simple
> NMAP
> > would work.
> >
> > -Wes
> >
> > -----Original Message-----
> > From: vinay mangal [mailto:vinay.mangal () eil co in]
> > Sent: Wednesday, September 01, 2004 4:27 AM
> > To: Pen
> > Subject: Tool to find hidden web proxy server
> >
> > Dear all,
> >
> > I am looking for a tool to find the hidden web proxy server in my local
> > network.
> >
> > Any hint will be useful.
> >
> > with regards
> > Vinay
>
>
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