Posts Tagged With ‘analysis’
Analyzing a failed TLS connection
Summary This post demonstrates how to correlate two or more trace files to analyze a broken connection. We identify the root cause and gather information about the network topology. Tracefiles are available at http://www.packet-foo.com/blog/TLS/Skype.zip We assume that the reader is familiar with TCP basics like session setup, retransmissions, window size etc.
Installing Moloch on Debian 9 Stretch
Moloch is a tool that builds on Elasticsearch to process large numbers of network packets, either from a live network or from imported PCAP files. This is how I installed it on a Debian 9 server.
Network Forensics Playbook – Banner Inspection and Client Origin
I recently did a hands-on-no-slides presentation at a very small security conference end of last year where I demoed some of the typical things I do when performing a network forensics analysis, using tshark, Wireshark and TraceWrangler. I’ll use these blog posts as a transcript of what I did, so that it’s easy to read […]
My packet analysis toolset
As any analyst (regardless of the topic being networks, IT security, forensics etc.) will tell you, it’s almost always a combination of tools that is used to get the results. And since I thought it might be useful, here’s my list of what I primarily use when analyzing packets.
How to Use Wireshark to Steal Passwords
Wireshark is a great tool to capture network packets, and we all know that people use the network to login to websites like Facebook, Twitter or Amazon. So there must be passwords or other authorization data being transported in those packets, and here’s how to get them.
Advanced display filtering
Wireshark has a lot of display filters, and the filtering engine is really powerful. You can filter on almost anything in a packet, and ever since the filter box started suggesting possible filter expressions it got really easy to find the one you wanted.
Determining network protocols
If you spent enough time using Wireshark or any other network analysis tool, you’ll sooner or later be able to even read bare hex dumps of packets, at least partially (it’s a little bit like Neo seeing the Matrix). So maybe you run across a text dump of a packet like this one: 0000 00 […]
Determining frame forwarding latency
In some situations the question arises how much a frame was delayed by a device it has to pass through, e.g. firewalls, loadbalancers and sometimes even routers and switches. Usually, novice network analysts think that for that you need to synchronize the clocks of the capture PCs down to microseconds or even better, but that […]
How millisecond delays may kill database performance
Mike, an old buddy of mine is one of the best database application development consultants I have ever met. We worked together for the same company for a couple of years before I got into network analysis and he started his own company. A couple of months ago I found out that there was going […]
Determining TCP Initial Round Trip Time
I was sitting in the back in Landis TCP Reassembly talk at Sharkfest 2014 (working on my slides for my next talk) when at the end one of the attendees approached me and asked me to explain determining TCP initial RTT to him again. I asked him for a piece of paper and a pen, […]