Snort Malicious Traffic Analysis Tool

Snort is an open-source Intrusion Detection and Prevention System (IDS/IPS) used to monitor network traffic and block malicious behavior. Here are the basic usage methods for Snort:

1. Install Snort:

   For Debian/Ubuntu systems, use the following command to install:

   sudo apt-get update  
   sudo apt-get install snort  
   

   For CentOS/RHEL systems, first install the EPEL repository, then use the following command to install:

   sudo yum install epel-release  
   sudo yum install snort  
   

2. Configure Snort:

The main configuration file for Snort is located at /etc/snort/snort.conf. First, create a backup:

sudo cp /etc/snort/snort.conf /etc/snort/snort.conf.bak  

Edit the configuration file using a text editor:

sudo nano /etc/snort/snort.conf  

Focus on the following settings in the configuration file:

• ipvar HOME_NET: Defines the protected internal network. For example, ipvar HOME_NET 192.168.1.0/24.
• ipvar EXTERNAL_NET: Defines the external network. Usually set to !$HOME_NET, meaning all addresses that are not in the internal network.
• var RULE_PATH: Defines the path of the rules files. For example, var RULE_PATH /etc/snort/rules.

Save and close the configuration file.

3. Download and update the rule set:

   Visit the Snort official website (https://www.snort.org/downloads) to download the latest rule set. Extract the downloaded rules to the /etc/snort/rules directory.

   To automatically update the rule set, you can use the pulledpork tool. First, install pulledpork:

   sudo apt-get install pulledpork (Debian/Ubuntu)  
   sudo yum install pulledpork (CentOS/RHEL)  
   

   Edit the pulledpork configuration file /etc/pulledpork/pulledpork.conf, set rule_url and the local rule directory. Then, run sudo pulledpork -c /etc/pulledpork/pulledpork.conf to update the rule set.

4. Start Snort:

   Start Snort in command line mode:

   sudo snort -c /etc/snort/snort.conf -i <INTERFACE> -A console  
   

   Where <INTERFACE> is the network interface to monitor (e.g., eth0 or enp0s3).

   To run Snort in the background and log to a file, use the following command:

   sudo snort -c /etc/snort/snort.conf -i <INTERFACE> -A fast -d -D -l /var/log/snort  
   

5. Analyze logs:

Snort will log detected events to log files. You can analyze the log files using a text editor or specialized tools such as Snorby, BASE, or Sguil.