Re: The Wisdom of Allowing an Open Port

[Kevin Wilcox <wilcoxkm () APPSTATE EDU>]

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On Wed, Nov 28, 2012 at 04:18:35PM -0600, Jim Pardonek wrote:

>    On our hospital campus we have an "open" wlan that requires the usual
>    rudimentary form of authentication (some email address and your name) to
>    gain access, similar to a hotel portal.  Some of the medical staff want us
>    to open port 1373 TCP so that they can access our GroupWise (I know)
>    servers using the regular client application.  Other than the normal
>    reasons for keeping everything except 80 and 443 closed, I'm looking to
>    see if anyone would like to weigh in on reasons for and against opening
>    this up.

All you need is one port to exfiltrate data.

When you can tunnel anything over SSL VPN connections on 443 then the
point is proven that just closing ports doesn't always have the intended
result.

That said, if you block 6667 - 6669, and someone comes in with a nasty
that only tries to phone home via IRC on those ports, you've done some
good.

Is there a reason you can't open 1373 to just your GroupWise servers?

kmw

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