Description
Prerequisites:
- Basic knowledge of TCP/IP and networking fundamentals.
- Familiarity with Linux environments (optional but helpful).
Tools and Technologies:
- Packet Capture Tools: Wireshark, tcpdump
- IDS Software: Snort or Suricata
- Environment: A PC or VM connected to a network (preferably a test network).
Steps:
- Set Up a Test Environment:
- Create a small, isolated network segment or use a home lab environment. You can use virtual machines connected through a virtual network in VirtualBox or VMware.
- Install Packet Capture Tools:
- Install Wireshark (GUI-based) or tcpdump (CLI-based).
- For Wireshark:
sudo apt-get install wireshark(on Linux) or download from its official website. - For tcpdump:
sudo apt-get install tcpdump(Linux).
- Collect Baseline Network Traffic:
- Start capturing packets on your network interface for a certain period of time.
- Analyze normal traffic to understand what typical patterns look like (e.g., HTTP requests, DNS lookups, HTTPS connections).
- Install and Configure Snort/Suricata:
- Choose Snort:
sudo apt-get install snorton Linux or follow the Snort documentation for other OSes. - Configure Snort by editing the
snort.conffile, specifying network variables, and including rule sets. - Test Snort by running it in packet logging mode first, and then in intrusion detection mode.
- Choose Snort:
- Develop Custom IDS Rules:
- Write simple rules to detect specific patterns in traffic. For example, a rule that triggers on a known malicious IP or a suspicious port scan.
- Example Snort rule format:
alert tcp any any -> any 80 (msg:"Possible SQL Injection"; content:"union select"; nocase; sid:1000001;)
- Generate Test Attacks:
- Use tools like Nmap to scan your test network and trigger alerts.
- Attempt simple web attacks on a test web server to verify that the IDS catches them.
- Analyze Alerts & Fine-tune:
- Review IDS alert logs, identify false positives, and adjust rules accordingly.
- Tune performance by disabling unnecessary rules and adding exceptions as needed.
Outcome:
You’ll learn how to monitor network traffic effectively, recognize normal versus malicious patterns, and manage a foundational intrusion detection capability.
