OT SIEM In One Picture: The Ultimate Data Source Map

Building an effective OT (Operational Technology) SIEM (Security Information and Event Management) starts with understanding your data sources. Without proper visibility into your network, detection efforts will fail. Here’s a breakdown of key data sources you need to collect logs from:

Application Server
Control Server
Data Gateway
Data Historian
Field I/O
Human-Machine Interface (HMI)
Intelligent Electronic Device (IED)
Jump Host
Programmable Logic Controller (PLC)
Remote Terminal Unit (RTU)
Routers
Safety Controller
Virtual Private Network (VPN) Server
Workstation

Each of these sources provides unique insights. Combining them ensures full visibility into your ICS (Industrial Control Systems) network.

You Should Know:

To effectively monitor and secure your OT environment, here are some practical commands and tools you can use:

1. Log Collection with Syslog:

Configure syslog on Linux to collect logs from network devices:

sudo apt-get install rsyslog
sudo systemctl enable rsyslog
sudo systemctl start rsyslog

Edit the syslog configuration file to define log sources:
```
sudo nano /etc/rsyslog.conf
```

2. Network Monitoring with Wireshark:

Capture network traffic from specific interfaces:
```
sudo wireshark -i eth0
```
Filter traffic related to ICS protocols (e.g., Modbus):
```
modbus
```

3. SIEM Integration with Elastic Stack:

Install Elasticsearch, Logstash, and Kibana (ELK Stack) for log aggregation:
```
sudo apt-get install elasticsearch logstash kibana
```

Configure Logstash to parse OT logs:

input {
file {
path => "/var/log/ot-logs/*.log"
start_position => "beginning"
}
}

4. MITRE ATT&CK for ICS Mapping:

Use the MITRE ATT&CK framework to map threats specific to ICS:

git clone https://github.com/mitre/attack-stack.git
cd attack-stack
python3 map_ics_threats.py

5. PLC Security with Nmap:

Scan for open ports on PLC devices:
```
nmap -p 502 <PLC_IP>
```

Check for vulnerabilities in ICS devices:

nmap --script ics-vuln-scan <target_IP>

What Undercode Say:

Building an OT SIEM requires a deep understanding of your network’s data sources. Start small by identifying and analyzing the easiest sources, then scale up. Use tools like Wireshark, Nmap, and the ELK Stack to monitor and secure your ICS environment. Always refer to frameworks like MITRE ATT&CK for ICS to stay ahead of threats. For more detailed guidance, explore resources like MITRE ATT&CK for ICS and Labshock’s OT SIEM Diagram.

Remember, visibility is key to effective cybersecurity in OT environments. Combine logs from all critical sources to ensure comprehensive protection.