Wireshark lessons learned

My masters classes keep sending us into Wireshark to analyze packet files. I thought I had a decent understanding of how to use Wireshark from some previous experience through work, but I keep finding new tricks as I try to figure out things about unknown protocols. Note that I’m using Wireshark 3.0.3, because that’s what’s installed in the lab infrastructure. I am aware that Wireshark 3.4 is out: my plan is to play with that version on my personal computer to see new goodies.

Copy and Paste

We keep needing to fill out spreadsheets of interesting things learned. We’re running Wireshark through a VDI infrastructure and I’m typically doing my homework on a laptop, so with limited screen real estate, even my touch typing skills aren’t helpful enough. The Copy capability in Wireshark lets me capture just the value for the field – highly useful for things like MAC addresses.

Protocol Hierarchy

Forget about randomly traversing files which including 100K packets – let the protocol hierarchy show likely interesting data points within the file. Filter by said protocol, and data patterns emerge. Worth calling out also the Conversations and Endpoints statistics areas, as well. Nice ways to get a holistic view of what’s going on in the file and what might be worth diving into.

Statistics -> …

We’re looking at SCADA pcap files, including BACnet. Delighted to find a traversal means for BACnet that let me inspect the devices and services seen in the pcap. I was less happy to see that iFix wasn’t in the list, and that Wireshark just treats it as plain TCP (again, with my older version of Wireshark, with its default set of dissectors, etc). Possibilities for expansion.

Expert Analysis

There’s a menu option for ‘Expert Analysis’ that I hadn’t played with before. Add its data, and then allow it to create filters to show just that data – voila. Evidence of TCP retransmissions? Yes, please.

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