Ignore it. It's likely that the software is not interpreting the latency correctly and is coming back with a false positive. You're behind a double-NAT network. The chances it is compromised from the outside is minuscule, unless you launched a fraudulent email payload that infected the router.
Out of curosity, what exactly does the Norton program say in regards to the "Network Compromised"? Having more details would be useful.
A man in the middle attack warning is often the result of an issue with a certificate. Though I have no idea what resource Norton is checking and seeing a certificate issue with. If you browse to your cable modem, do you get any security warnings?
I think the address is: https://192.168.0.1 (someone please correct me if that is wrong).
Yeah when you browse using https (the "s" is the important part) you are saying that you want a secure communication channel and your transmission to that website to be encrypted. Browsers use certificates which contain encyprtion keys and identity information. The browser will validate, for example, that https://google.com is really Google and not someone who intercepted your traffic and put up a fake page and is now recording what you type. If they impersonate a bank website for instance, they could get your banking credentials.
But HughesNet doesn't own 192.168.0.1, anyone can use that IP address because that's a private IP address space. So your browser will warn you that the certificate doesn't match correctly, which is the warning that you saw (it will still give you an option to continue to the site). I suspect Norton is picking that up as well. When it validates your network, it sees that the gateway you use to connect to the internet has a mismatched certificate and shows you that error. If Norton gives you an option to "Trust" that network, you can probably select that option so that the warning goes away.
Since it is a security concern though, hopefully one of the Moderators can confirm this behavior or otherwise explain it, but I'm fairly confident that you can ignore it.
Firefox provides a similar warning when there's either no certificate or the domain doesn't match when using secure http, as I'd suspect most browsers would.
The correct way to access the System Control Center embedded in the modem is using http (no 's'):
Edit: That second one is actually incorrect, but it's something like that.