From: Dominick Alfano (dommaillist@gmail.com)
Date: Thu Aug 16 2007 - 06:55:53 EDT
ganesh mahadevan wrote:
> Hi,
>
> I need some guidance. I am carrying out a pen test of a network
> interconnect setup. The scenario is this:
>
> An internal network is connected to an external network through
> serial to Ethernet converters and two relays (one on the outward
> facing side is normally open and one on the inward facing side is
> normally closed). There is an intermediate server between these two
> relays. These relays close and open for a certain period of time
> depending on a pearl script running on the internal gateway. This
> intermediate server is connected to the gateways of both networks
> through the serial to Ethernet converters. The user logs into the
> outward facing gateway, sends data in a particular format. This is
> sent further through the relays and the serial to Ethernet converter
> to the intermediate server. The intermediate server does input
> validation and accepts data only if it meets this criteria. Once the
> relay on the inner side closes (and the relay on the outer side
> opens), this data is then sent further onto the internal network.
>
> I hope this description is clear. I need some pointers on how to
> pentest this setup and what could be the potential pitfalls in this
> setup. Any help would be welcome and appreciated.
>
> Thanks
>
> Ganesh
>
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>
Ganesh,
It sounds to me, that your basically describing a complete half duplex
setup (Data can only be Transmitted or Received, never both at the same
time right?). Actually, it sounds more along the lines of an older
network that I've seen a couple times running DDR over ISDN. Where
packets have to meet certain criteria in order for data streams to be open.
I could be completely wrong about both of these, but the problem with
both, in my humble opinion, is manageability of network overhead. It
doesn't queue/send packets fast enough causing a lot of "lag" (I guess
you would say), therefore more susceptible to Denial of Service attacks
against server services, or even better, multiple service simultaneous
connections (Eg. DoS ftp and smtp and ssh at once). By what your
describing again, it sounds like the network / server cannot handle too
much of this type of attack.
I tried....ha ha :)
- Dominick
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