Safety vs Security Is Dead: Why Operational Resilience Is the Only OT Priority That Matters + Video

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Introduction

For decades, Operational Technology (OT) professionals have been taught that safety must always take precedence over cybersecurity. But this binary thinking creates dangerous blind spots—a system can be perfectly safe today yet completely vulnerable to a ransomware attack that shuts down a power grid tomorrow. The real objective is not choosing between safety and security but engineering Operational Resilience that balances safety, reliability, performance, availability, and security as interdependent pillars.

Learning Objectives

  • Understand why the “Safety vs. Security” framework undermines true OT risk management and how reliability acts as the missing link
  • Learn practical Linux and Windows commands to assess OT asset health, network segmentation, and system integrity without disrupting operations
  • Implement a step-by-step operational resilience checklist that integrates safety instrumented systems (SIS) with cybersecurity monitoring

You Should Know

  1. Mapping the Five Pillars: Safety, Reliability, Performance, Availability, Security

The post argues that safety is non‑negotiable, reliability essential, performance sustains the business, security protects the operation, and resilience brings them together. In OT environments (ICS, SCADA, DCS), this means moving from siloed metrics to unified dashboards.

Step‑by‑step guide to assess your current state:

  1. Inventory critical assets – Use `nmap` (Linux) or `ping sweep` (Windows PowerShell) to discover live OT devices without aggressive scanning that may crash legacy PLCs. 
    Linux: slow, low‑rate discovery
sudo nmap -sn -T0 192.168.1.0/24 --max-retries 1 --host-timeout 30s

    Windows PowerShell: ICMP sweep
1..254 | ForEach-Object { Test-Connection -ComputerName "192.168.1.$_" -Count 1 -Quiet }

  2. Check Safety Integrity Level (SIL) compliance – Verify that safety instrumented functions are not bypassed by security appliances. On a Siemens S7 or Rockwell PLC, use vendor CLI tools (e.g., `s7‑ping` on Linux):

    sudo apt install s7‑utils
s7‑ping 192.168.1.100  confirms PLC reachability without writing

  3. Monitor Reliability metrics – Track controller scan time and CPU load. On a Windows engineering workstation running FactoryTalk or WinCC, use Performance Monitor:

    Get-Counter -ComputerName "OT-ENG-01" "\Processor(_Total)\% Processor Time" -SampleInterval 2 -MaxSamples 10

    A sudden increase may indicate a malicious process or failing hardware.

  4. Validate Availability – Test redundant pairs (e.g., primary/backup PLCs). Use `ping` with timestamps to detect switchover delays:

    while true; do ping -c 1 192.168.1.101 | grep time >> ping_log.txt; sleep 1; done

  5. Security baseline – Run a read‑only Nessus scan (policy: “OT Industrial Basic”) to identify open ports without writing registers. Review findings against Purdue model zones.

  6. Breaking the “Safety vs. Security” Binary with Cyber‑Informed Engineering

Puneet Tambi’s post highlights that safety and security are not trade‑offs but co‑requisites. Cyber‑Informed Engineering (CIE) embeds security into safety‑critical designs. For example, a burner management system (BMS) with a safety PLC should also log authentication events.

Step‑by‑step configuration example (Windows + Linux hybrid):

  1. Centralize logs from safety PLCs to a read‑only syslog server. On the Linux syslog server: 
    sudo nano /etc/rsyslog.d/50-ot.conf
Add: $template RemoteLogs,"/var/log/ot/%HOSTNAME%/%PROGRAMNAME%.log"
Restart: sudo systemctl restart rsyslog

  2. Forward Windows Event Logs (from OPC servers or HMIs) using `wevtutil` and netcat:

    wevtutil qe System /f:text /c:1 | nc 192.168.10.200 514

    (Ideally use Winlogbeat for production, but this quick command tests connectivity.)

  3. Create a safety‑security correlation rule – On the Linux server, use `fail2ban` style monitoring for repeated safety valve commands from unauthorized IPs:

    sudo journalctl -f | grep --line-buffered "SAFETY_TRIP" | while read line; do echo "$line" | grep -q "192.168.0.200" && sudo iptables -A INPUT -s 192.168.0.200 -j DROP; done

  4. Test without interrupting operations – Use a simulation environment (e.g., OpenPLC on a Raspberry Pi) to inject false safety trips and verify that security controls do not inhibit genuine emergency shutdowns.

3. Hardening Reliability While Maintaining Performance

Many OT cyber controls (e.g., application whitelisting, antivirus scans) degrade controller performance. The post calls for balancing performance sustainability with security.

Linux command to measure latency introduced by security tools on a gateway connecting field devices:

 Measure round‑trip time with and without packet inspection
tc qdisc add dev eth0 root netem delay 10ms  simulate security appliance
ping -c 100 192.168.1.1 | grep avg
tc qdisc del dev eth0 root netem
ping -c 100 192.168.1.1 | grep avg

Windows PowerShell script to check AV scan impact on HMI responsiveness:

$before = (Get-Date).Millisecond
Start-Process "C:\Program Files\HMI\view.exe" -Wait
$after = (Get-Date).Millisecond
Write-Host "Launch time: $($after - $before) ms"
 Temporarily disable real‑time scanning on the HMI folder (only if network isolated)
Set-MpPreference -ExclusionPath "C:\HMI_Data"

Mitigation strategy – Use application allowlisting (e.g., `auditd` on Linux, AppLocker on Windows) instead of signature‑based scanning. On Windows:

 Enable AppLocker rules for known HMIs
New-AppLockerPolicy -RuleType Exe -User Everyone -Path "C:\Program Files\HMI.exe" -Action Allow
  1. API Security in OT: The Hidden Threat to Performance

Modern OT systems expose REST APIs (e.g., OSIsoft PI Web API, Ignition Gateway). Unauthenticated API calls can flood historians, impacting performance and availability.

Test for API rate limiting (Linux using `curl` and jq) :

for i in {1..1000}; do curl -s -o /dev/null -w "%{http_code}\n" http://192.168.1.50/api/values; done | sort | uniq -c

If you see many `200` (instead of `429` Too Many Requests), the API lacks throttling.

Hardening step – Implement an API gateway with `nginx` rate limiting on the Linux jump host:

sudo apt install nginx
sudo nano /etc/nginx/sites-available/ot-api

Add:

limit_req_zone $binary_remote_addr zone=otapi:10m rate=5r/s;
server {
location /api/ {
limit_req zone=otapi burst=10;
proxy_pass http://internal-ot-api:8080/;
}
}

5. Cloud Hardening for Hybrid OT/IT Architectures

As OT data moves to cloud dashboards (Azure IoT, AWS SiteWise), misconfigured IAM roles become a reliability risk. An attacker who deletes a cloud asset can blind operators.

Step‑by‑step hardening checklist:

  1. Enforce MFA for all cloud service accounts accessing OT data. Use Azure CLI to verify conditional access policies: 
    az ad conditional-access policy list --query "[?state=='enabled']"

  2. Set up service‑side encryption and immutable backups. On AWS S3 for historian exports:

    aws s3api put-bucket-versioning --bucket ot-historic-data --versioning-configuration Status=Enabled
aws s3api put-bucket-encryption --bucket ot-historic-data --server-side-encryption-configuration '{"Rules":[{"ApplyServerSideEncryptionByDefault":{"SSEAlgorithm":"AES256"}}]}'

  3. Monitor cloud API calls for unauthorized deletion. On Azure, export Activity Logs to a Log Analytics workspace and alert on MICROSOFT.RESOURCES/DEPLOYMENTS/DELETE.

6. Vulnerability Exploitation and Mitigation in OT Environments

The post’s emphasis on resilience means preparing for a successful breach. Focus on containment rather than just prevention.

Simulate a DoS attack on a test PLC (Linux with hping3) :

sudo hping3 --flood -S -p 102 192.168.1.100  S7comm port 102

Mitigation – Deploy industrial IDS like `Snort` with OT rules:

sudo apt install snort
sudo wget -O /etc/snort/rules/ot-rules.txt https://raw.githubusercontent.com/digitalbond/Quickdraw-Snort/master/snort.rules
sudo snort -c /etc/snort/snort.conf -i eth0 -A console

Windows‑side mitigation – Enable Windows Firewall with advanced security to block unknown traffic to the HMI:

New-1etFirewallRule -DisplayName "Block S7 from non-engineering" -Direction Inbound -Protocol TCP -LocalPort 102 -Action Block -RemoteAddress 192.168.2.0/24

7. Building Operational Resilience Through Cross‑Functional Drills

Resilience is not a technical metric but a team capability. Run quarterly “Purple Team” exercises involving safety engineers, control engineers, and IT security.

Sample drill script (Linux controller orchestrating a simulated safety valve exercise) :

!/bin/bash
 Simulate a pressure spike (read-only test)
modbus read 192.168.1.10 40001 1  read pressure register
if [ $? -eq 0 ]; then
echo "Simulating safety trip - no actual output"
logger "OT DRILL: Safety condition detected by security tool"
else
echo "PLC unreachable - check network resilience"
fi

Windows PowerShell equivalent for HMI alert verification:

$alert = Read-Host "Inject a fake 'High Temp' alarm? (y/n)"
if ($alert -eq 'y') { Write-EventLog -LogName "OT Alarms" -Source "Drill" -EventId 9999 -Message "Drill: High Temperature" -EntryType Warning }

After the drill, document “resilience gaps” (e.g., slow operator response to cyber‑induced alarms) and update runbooks.

What Undercode Say

  • Key Takeaway 1: The “Safety vs. Security” debate is a false dichotomy; operational resilience requires balancing safety, reliability, performance, availability, and security as equal citizens, not a hierarchy.
  • Key Takeaway 2: Practical resilience emerges from engineering choices—using read‑only scans, rate‑limited APIs, immutable cloud backups, and cross‑functional drills—not from buying more security appliances.

Analysis: Puneet Tambi’s post cuts through decades of OT dogma. Safety absolutely remains non‑negotiable, but framing it as “always first” has allowed reliability and security to atrophy. Real‑world incidents (Colonial Pipeline, German wind farm attack) show that a safety‑only mindset leaves systems brittle. The future lies in cyber‑informed engineering where safety PLCs log authentication failures and reliability metrics feed security analytics. Organizations that adopt this five‑pillar model will recover faster from ransomware and human error alike. The missing piece he highlights—reliability—is often the bridge between safety and security; a reliable system has predictable behavior, which makes anomalies detectable. Moving forward, OT leaders must stop asking “Safety or security?” and start asking “How do we make safety, reliability, performance, availability, and security co‑operate under resilience?”

Prediction

  • +1 OT cybersecurity budgets will shift 40% toward reliability engineering and observability tools by 2028, merging IT’s SRE practices with ICS safety standards.
  • -1 Without standardized metrics for operational resilience, many organizations will fall into “resilience theatre” – buying solutions without changing engineering culture, leading to false confidence.
  • +1 The ISA/IEC 62443 framework will add a new “Resilience Level (RL)” alongside Security Levels, forcing vendors to certify products against coordinated safety‑security failures.
  • -1 Small and mid‑sized OT operators (water, food processing) will continue to view resilience as too expensive, remaining stuck in the safety‑vs‑security binary until a major incident forces regulatory change.
  • +1 Cross‑functional “Resilience Engineering” roles will emerge, combining P.E. licenses with CISSP certifications, becoming the most sought‑after talent in critical infrastructure.

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