Wireshark is the most widely used network capture and protocol analyzer on the market. It is used by IT and Network administrators to troubleshoot network connectivity issues and by Network Security analysts to dissect network attacks. This free and open source application is so widely used in the industry because it works. It is cross platform, meaning that it runs on Windows, Mac, Linux and FreeBSD.
This course is an introduction to the application and goes over the basics to get you started capturing and analyzing network traffic. It will build your base by explaining the theory behind how networks work and then get you in to real world applications of the software.
In this course you will learn:
This lecture covers what wireshark is, it's history, what its used for and the graphical interface.
In this lecture we discuss the Open Systems Interconnect (OSI) Model and how it relates to wireshark.
This lecture sets up the nuances of installing Wireshark on multiple platforms. We will dive in to installing on Windows 7 and also the need for WinPCAP.
This video goes over installing the X11 client XQuartz and installing Wireshark so that it works properly with XQuartz.
Instructions on how to install and run wireshark on Ubuntu 12.04
01:25 - sudo apt-get install wireshark
02:22 - wireshark
This lecture will discuss the theroy behind placing wireshark in the proper location on a network for maximum packet capture.
Here we will set up your first network capture. We will discuss many of the options related to packet captures.
Capture filters are great for capturing a small subset of traffic on a very congested network. This lecture will explain how to build capture filters and how to apply them in wireshark. See some of the supplemental resources for more detialed information on all the filters available.
Once you have captured traffic from the network, wireshark has a whole host of tools that allow you to manipulate the data. This lecture will show you some of the common tools such as time shifting, changing column preferences and merging PCAP files.
Display filters allow you to display only the packets you want to see or to filter out packets that you don't want to see. In this lecture we will discuss several ways to build display filters and how to save them for future use.
In your captured data there may be several computers all talking at once. Wireshark has the ability to rebuild these "conversations" and show you the plain text data. This lecture will show you how to rebuild the conversations and see what conversations happened on the network.
One of the main functions of networks is to transfer files between two end points. While the wireshark interface shows you the individual packets it may be difficult to see what was actually transmitted. Wireshark has several tools that will rebuild files that were transmitted over HTTP and SMB. This lecture will show you two ways of rebuilding files from a PCAP.
Tshark is a command line version of wireshark that comes bundled with the application. It is very handy for scripting and carving smaller pcap files out of larger pcap files. This lecture will demonstrate the power of this program.
01:13 - tshark --help
02:30 - ls -lah
03:11 - tshark -r large.cap -R http -w small.pcap
03:32 - ls -lah
Thank you so much for taking my course. If you would like to keep up with me you can signup for my newsletter and I will send you updates to the course and sneak peaks/discounts on future courses. Signup here.
In this lecture we will go over some advanced tshark uses. Discussing field extraction using tshark and organizing the output.
02:53 - “tshark -r http.pcap -T fields -e http.request.method”
03:56 -“tshark -r http.pcap -T fields -e http.request.method | sort | uniq -c”
05:30 - “tshark -r http.pcap -T fields -e http.request.uri”
07:21 - “tshark -r http.pcap -R “http.request.method == “GET”” -T fields -e ip.dst”
07:44 - “tshark -r http.pcap -R “http.request.method == “GET”” -T fields -e ip.dst | sort | uniq-c”
In this lecture I discuss using wireshark and Virus Total to discover if any computers on your network are communicating with known bad IP addresses.
An introduction to TCPDUMP and how it is different from wireshark.
Start your first capture using TCPDUMP and learn the common command line switches.
00:30 - man tcpdump
03:48 - tcpdump -D
04:26 - tcpdump -i en0
05:05 - tcpdump -i en0 -n
05:37 - tcpdump -i en0 -n -vvv
06:16 - tcpdump -i en0 -n -vvv -w test.pcap
07:16 - tcpdump -i en0 -n -vvv -s 96 -w test.pcap
Create filters for TCPDUMP using the Berkley Packet Filter (BPF) syntax.
02:50 - tcpdump -i en0 -n -vvv host 10.0.1.21
03:14 - tcpdump -i en0 -n -vvv host 10.0.1.21 and port 80
04:17 - tcpdump -i en0 -n -vvv net 10.0.1.0/24 and port 80
Use TCPDUMP to carve smaller pcap files out of much larger datasets.
00:28 - ls -lah
01:13 - tcpdump -r sansholidayhack2013.pcap tcp and port 80
01:37 - tcpdump -r sansholidayhack2013.pcap -w http.pcap tcp and port 80
01:41 - ls -lah
02:23 - tcpdump -r sansholidayhack2013.pcap -w badip.pcap host 188.8.131.52
02:26 - ls -lah
Cheat sheet for TCPDUMP commonly used commands and filters.
Quiz you on TCPDUMP command line switches and filter syntax.
Kyle Slosek is a security practitioner with several years of experience in enterprise IT environments. Kyle works for a large IT firm in the DMV area and had done everything from certification and accreditation to pentesting testing and forensics. He holds a BS in Information Technology and an MS in Information Assurance as well as several industry certifications.
I got in to computers at a young age. When I was young I was fascinated with the family computer and proceeded to build my own with used parts I found lying around or purchased on eBay. I was first interested in security after a home server I had built was hacked. I was hosting my own website on a old desktop I had lying around when I realized that a hacker had defaced my site. I then began my long security career.
I am very passionate about STEM education and regularly spend time in high schools talking to students about IT and IT Security. I sit on the board of advisors for the Montgomery County MD Academy of Information Technology and in that role help place high school students in well paying and interesting internships.