Published: 2009-10-25. Last Updated: 2009-11-01 21:29:27 UTC
by Lorna Hutcheson (Version: 1)
Port 80 and 443 are ports generally associated with "the Internet". Port 443/HTTPS is the HTTP protocol over TLS/SSL. Port 80/HTTP is the World Wide Web. Let's face it, port 80/443 are generally a given for being open on any type of filtering device allowing traffic outbound on your network. If web servers are being hosted, connections will be allowed inbound to those web servers. They are also two ports that pose a significant threat(s) to your network.
One reason for such a threat, is the very fact that we just mentioned: everyone generally associates it with the Internet and web traffic and its usually open. Sadly, it doesn't get watched that closely. I have heard the statement many times "its just people surfing the web and we ignore it cause there is too much traffic." The sad reality is that more often than not, the threat will come from people on your network surfing the web. The rise in browser based attacks is staggering to say the least.
For those that do want to watch it close, that poses a challenge as well. How do you filter? What do you filter? How do you do analysis on the traffic? Let me pose a example to you. I looked at a piece of malware about three years ago that used base64 encoded html comments, on a very benign web page, to pass commands. How do you detect that? Some software automatically defaults to port 80 if the primary port is available.
The above two threats applies to port 80 and 443 traffic. Now, let's just focus on 443 for a minute. It's encrypted traffic which means you can't read it. So what do you do? Unless you have a proxy on your network where you can inspect the traffic at that point or run a host based IDS etc., your other network tools are blind to what is there.
I have become a big fan and proponent of visual analysis for network traffic. With the amount of traffic we have on our networks today, visual analysis is in my opinion, one of the few viable options for trying to discern trends in traffic. Port 80 and 443 are prime candidates for that analysis. Things such as establishing what is normal for traffic loads, time of day, websites visited etc. can all be great baselines to know when something different starts to happen.
If you have any comments or suggestions for port 80 and 443, then please let us know. Also, there are other services that you know of that run on port 80, please post those as well!
