Case of the Large Header

Just because you can do something doesn't always mean you should. One such example of this is using large HTTP headers. While the HTTP specification itself doesn't set boundaries, most web servers have default limits around 8 KB. Other devices in the path such as firewalls/WAFs, proxies, and load balancers also have similar limits.   Problem The application testers were receiving a reset error. Their application and web server logs did not show any problems.   Analysis The first question asked was, "If the web server isn't sending the reset error, what is?" In this case we found there were several devices in the path including a domain firewall and a load balancer. The firewall admin saw two-way traffic hitting an accept rule and passing through. That left the load balancer.┬áThe load balancer admin confirmed via a packet capture that it was, in fact, sending a reset near the end of the TCP stream. Why would the load balancer send a reset? A load balancer does exactly that....balances...
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Packet Threat Analysis

Everyone needs to do some housekeeping at different points, and I figured it was time I did some a basic security sweep of my setup. To get started, I performed a quick packet capture on the very server that hosts this blog. I decided to give one of CloudShark's newer and more distinct features a spin with my recently created account; their Threat Assessment tool. I thought it would be interesting to pit this against PacketTotal as well. These are both great tools with similar, but also different purposes. At the time, I had SSH and web ports open along with a few other unused ports for various common services. The only true security measure in place was a few basic iptables rules. CloudShark What I Liked: Up front, quick severity level rating dashboard Brief descriptions of issues which helps puts everything in laymen's terms World map view Privacy settings External references to source data and additional information Ability to view the...
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