Still Relevant, Still Critical: A Must-Read on ICS Cybersecurity

The SANS Institute’s White Paper on the Five ICS Cybersecurity Critical Controls (by Robert M. Lee and Tim Conway) remains a cornerstone resource for securing Industrial Control Systems (ICS) and Operational Technology (OT). The framework emphasizes outcome-focused, risk-based strategies rooted in real-world incidents.

The Five Critical Controls:

1. ICS Incident Response – Scenario-driven, not checklist-based.

1. Defensible Architecture – Focus on resilience, not just segmentation.
2. Network Visibility & Monitoring – Protocol-aware and physics-aware.
3. Secure Remote Access – MFA, choke-points, and break-inspect strategies.
4. Risk-Based Vulnerability Management – Prioritize real risk over CVEs.

You Should Know:

1. ICS Incident Response

• Practice: Use `log2timeline` (Plaso) for ICS forensic timeline analysis:

  log2timeline.py --storage-file timeline.plaso /path/to/evidence
  

• Command: Monitor ICS logs with `journalctl` (Linux):

  journalctl -u modbus.service --no-pager -f
  

2. Defensible Architecture

• Tool: Implement Unidirectional Gateways (Data Diodes) to enforce one-way traffic.
• Command: Check Linux firewall rules (iptables):

  iptables -L -n -v | grep DROP
  

3. Network Visibility & Monitoring

• Tool: Use Wireshark with ICS protocol dissectors (MODBUS, DNP3):

  wireshark -k -i eth0 -Y "modbus || dnp3"
  

• Command: Detect anomalies with `snort` (ICS rules):

  snort -c /etc/snort/snort.conf -A console -q
  

4. Secure Remote Access

• Practice: Enforce Multi-Factor Authentication (MFA) for SSH:

  sudo nano /etc/ssh/sshd_config 
  Add: 
  AuthenticationMethods publickey,keyboard-interactive
  

• Tool: Use Guacamole for secure web-based access.

5. Risk-Based Vulnerability Management

• Command: Scan for ICS vulnerabilities with nmap:

  nmap -sV --script vulners <target>
  

• Tool: OpenVAS for ICS-specific risk assessment.

What Undercode Say:

• “Defensible > Secure”: Harden ICS systems with `chroot` jails:

  chroot /secure_path /bin/bash
  

• Monitor PLCs using `pcp` (Performance Co-Pilot):

  pminfo -f modbus.registers.read
  

• Windows ICS Security: Disable SMBv1:

  Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol
  

• Log Aggregation: Forward ICS logs via rsyslog:

  sudo nano /etc/rsyslog.conf 
  Add: 
  . @<log-server>:514
  

Expected Output: A resilient ICS environment with continuous monitoring, secure access, and actionable incident response.

Reference: SANS ICS Critical Controls

References:

Reported By: Ashok Kumar – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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