cyber-security-resources/threat_hunting/zeek-tips.md

Zeek

Process a Pcap

The following command will output Zeek logs in the current directory. Because of this we recommend creating a new directory first, in this case the logs directory.

mkdir logs
cd logs

Next, modify the following command to give the correct path to your pcap file. You only need to change the pcap path. Do not change the word local.

zeek -r /path/to/sample.pcap local

The Zeek arguments are:

• -r /path/to/sample.pcap is the path to the pcap you want to process.
• local is the name of the Zeek script to use to process the pcap.

Depending on what you are doing next you may want to either stay in the current directory to work directly with the newly generated Zeek logs, or you may want change back to your original directory.

cd ..

Here is a sample of the logs generated that you can find in your logs directory:

• conn.log - Connection information for TCP, UDP, and ICMP
• dns.log - DNS requests & responses
• http.log - HTTP requests
• ssl.log - SSL/TLS certificate information

You can find more information about these logs in Zeek's documentation or in Corelight's Cheatsheets.

RITA

Import Zeek Logs

The following command assumes you have your Zeek logs in the logs directory and you want to name your dataset sample.

rita import logs sample

Viewing Results

In general, the syntax for viewing results is:

rita COMMAND dataset

Where COMMAND is one of:

• show-beacons - Print hosts which show signs of beaconing activity
• show-exploded-dns - Print dns analysis. Exposes covert dns channels
• show-long-connections - Print long connections and relevant information
• show-strobes - Print strobe information
• show-useragents - Print user agent information

These are the commands you will find most useful in these labs. You can run rita --help to see the full list of commands you can use.

You can also run rita COMMAND --help to view detailed usage for each command. Most of the commands support these options:

• -H, --human-readable - Prints the results in an ASCII table that is easier to read on the command line. By default RITA outputs CSV format that is suitable for importing into a spreadsheet or further processing with the likes of grep, cut, and sort.
• --limit 10 - Sets the number of results that are output. This is equivalent to piping to tail but will return results quicker.
• --no-limit - By default the limit is set to 1000 but if you wish to see all results you can use this flag.

HTML Report

Run the following command on your dataset. In this case the dataset name is "sample".

rita html-report sample

This will generate HTML files with the results from the dataset. It should open the report in a web browser for you. But if you need to you can open this file manually: sample/index.html

Click on the dataset name "sample" and you should see this screen.

Navigate between the different reports using the labels on the top of the screen. For instance, clicking Beacons will display a table with the beacon results in it.