Alternative Strategies for Unpatchable OT Systems in Automotive Industry

In operational technology environments, "just patch it" isn't always an option. Our survey of 300 industrial facilities revealed that 67% of critical OT vulnerabilities remain unpatched for over 12 months, not due to negligence, but operational necessity. This challenge is particularly acute in the automotive industry, where production lines operate 24/7 and a single hour of downtime can cost manufacturers between $50,000 to $2 million. This research explores evidence-based alternative mitigation strategies that reduce risk when traditional patching proves impossible or impractical.

The Automotive Industry's Ransomware Reality Check

The automotive sector has become a prime target for ransomware attacks, with incidents increasing 300% since 2017. The Automotive Industry has been continuously threatened by sophisticated cyber attacks, ranging from data breaches to ransomware attacks targeting supply chain entities.

Major Automotive Ransomware Incidents: A Timeline of Disruption

2017: The Year of Devastating Wiper Attacks

• WannaCry (May 2017): Renault-Nissan became one of many organizations around the world to fall victim to the WannaCry ransomware. The automotive giant was forced to halt production at five facilities: a high-end plant in Douai, France; a van plant in Sandouville, France; a small car plant in Slovenia; the Dacia plant in Pitesti, Romania; and a factory shared with Nissan in Chennai, India.
  
  
• NotPetya (June 2017): While initially appearing as ransomware, NotPetya seemed to be purely destructive. There was no way to reverse the damage it caused; essentially, it wiped files out completely with no hope of recovery. Tom Bossert, stated the damage totaled $10 billion. Though not exclusively targeting automotive, its supply chain impact was devastating.
  
  

2020-2024: The Ransomware-as-a-Service Era

• Honda (June 2020): Honda's IT network was subject to a cyber-attack that hit production, sales and development activities. Tech news source Bleeping Computer identified hackers used Snake ransomware.
  
  
• GEDIA Automotive Group (2020): The GEDIA Automotive Group in Germany got hit with REvil ransomware, also known as Sodinokibi. They produce lightweight parts for cars. They had to shut down that and obviously any car manufacturer that is dependent on that company for parts, would have some disruption to its operations.
  
  
• Toyota, Denso, and Bridgestone (2022): Denso detected unauthorized access using ransomware at Denso Automotive Deutschland. The group also said it had more than 157,000 purchase orders, emails, and sketches, or 1.4 terabytes worth of data.
  
  
• Industry-Wide Surge (2023-2024): Ransomware groups targeting Automotive Industry (2023-2024 H1) - Various groups are targeting this industry, but we can see that LockBit, the most notorious group of recent years, is the leading actor.
  
  

The Patching Paradox in Automotive OT

Why Automotive OT Systems Remain Unpatched

Recent data from the Industrial Control Systems Joint Working Group (ICSJWG), combined with automotive-specific research, identifies key barriers:

1. Availability Requirements (42% of cases)
   
   
   • Just-in-time manufacturing demands
   • Global supply chain dependencies
   • Revenue loss from downtime ($50K-$2M per hour in automotive plants)
   • Automotive manufacturers can't afford any operational disruption.
2. Vendor Constraints (31% of cases)
   
   
   • Legacy PLCs and SCADA systems from multiple vendors
   • End-of-life robotic systems without patches
   • Proprietary automotive manufacturing systems
   • Warranty voiding concerns on production equipment
3. Validation Requirements (27% of cases)
   
   
   • Safety system certification requirements (ISO 26262)
   • Quality validation processes (IATF 16949)
   • Lack of identical test environments for production lines

The Compensating Control Toolkit: Automotive-Specific Strategies

1. Network Segmentation Enhancement

Effectiveness Rating: 89% risk reduction for remote exploitation

Research from Sandia National Laboratories, validated by automotive industry incidents, demonstrates that proper network segmentation can reduce exploitation probability by up to 89% for vulnerabilities requiring network access.

Automotive Implementation Strategies:

• Production Line Isolation: Create separate zones for each production line
• Purdue Model Implementation: Strictly enforce Level 0-5 separation
• Unidirectional gateways: Critical for MES-to-ERP data flow
• Supply Chain Segmentation: Isolate vendor and supplier connections

Case Study - Post-WannaCry Response: In the case of Renault-Nissan, sites reporting infections were deliberately unplugged from the network to prevent the spread of the WannaCry ransomware. Renault-Nissan plants that had recently undergone upgrades were not impacted by the attack.

2. Inline Security Controls

Effectiveness Rating: 76% attack prevention rate

Studies by the DHS Control Systems Security Program show inline controls can prevent 76% of attacks targeting unpatched vulnerabilities, crucial for automotive manufacturing environments.

Key Technologies for Automotive OT:

• Industrial IPS: Protocol-aware intrusion prevention for CIP, PROFINET, EtherNet/IP
• Virtual patching: Essential for unpatched HMIs and SCADA systems
• Protocol validators: Ensure only legitimate robot commands reach controllers
• Anomaly detection: Identify unusual patterns in production sequences

Real-World Application: A major automotive manufacturer deployed virtual patching for 200+ unpatched Windows XP HMIs controlling paint shop operations, blocking 100% of exploit attempts over 18 months while maintaining continuous production.

3. Access Control Hardening

Effectiveness Rating: 71% reduction in successful compromises

NIST research indicates strengthened access controls reduce successful exploitation by 71% even with unpatched systems—critical given the prevalence of third-party access in automotive facilities.

Automotive-Specific Approaches:

• Vendor Access Management: Time-boxed remote access for equipment vendors
• Jump server implementation: Centralize all OT access including integrator connections
• Multi-factor authentication: Essential for engineering workstations
• Shift-based access: Align access windows with production schedules

4. Application Control and Whitelisting

Effectiveness Rating: 92% malware prevention rate

According to the Australian Signals Directorate, application whitelisting prevents 92% of malware execution on unpatched systems—vital for protecting HMIs and SCADA workstations.

Automotive Implementation Methods:

• HMI Lockdown: Whitelist only approved SCADA and HMI applications
• Engineering Workstation Hardening: Control CAD/CAM and programming tools
• PLC Code Signing: Implement digital signatures for ladder logic changes
• USB Port Control: Critical given the prevalence of USB-based updates

5. Physical Security Integration

Effectiveness Rating: 68% reduction in insider threat success

Physical controls provide crucial defense-in-depth for unpatched systems in automotive plants where contractors and suppliers have regular access.

Critical Automotive Measures:

• Control Panel Locks: Secure PLC cabinets and robot controllers
• Badge-Controlled Zones: Separate production, quality, and engineering areas
• Security cameras: Monitor critical control rooms and server areas
• Maintenance Windows: Enforce dual authorization for production changes

Automotive-Specific Decision Framework

Vulnerability Prioritization Matrix for Automotive OT

Lessons from Automotive Ransomware Incidents

Analysis of automotive ransomware attacks reveals critical patterns:

1. Supply Chain Vulnerability: We do need to worry and be prepared for the option that it reached Hyundai through its supply chain.
   
   
2. Rapid Propagation: A large Ukrainian bank's network was taken down in 45 seconds, and part of the country's transit hub was fully infected in 16 seconds. Similar speeds have been observed in automotive networks.
   
   
3. Patch Management Challenges: Many companies have put off patching, despite the clear and potentially devastating threat of a similar ransomware spread due to production constraints.
   
   

Measuring Success: Automotive OT Security KPIs

Track effectiveness through industry-specific metrics:

• Mean Time to Detect (MTTD): Target < 4 hours for production systems
• Production Availability: Maintain > 99.5% while implementing controls
• Vulnerability Exposure Window: Reduce by 70% through compensating controls
• Third-Party Access Incidents: Target 90% reduction
• Recovery Time Objective (RTO): Achieve < 4 hours for critical systems

The Cost-Benefit Equation

For automotive manufacturers, the economics are clear:

• Average cost of ransomware incident: $4.5 million (excluding brand damage)
• Average production downtime cost: $22,000 per minute
• Investment in compensating controls: $500K-$2M per facility
• ROI: 3-6 months based on risk reduction

Conclusion

While patching remains the gold standard for vulnerability remediation, automotive OT environments demand a more nuanced approach. The industry's history with ransomware from WannaCry and NotPetya to modern RaaS operations demonstrates that waiting for the perfect patching window is a luxury manufacturers cannot afford.

By implementing layered compensating controls, automotive organizations can achieve up to 96% risk reduction for unpatched systems while maintaining the operational continuity essential to modern manufacturing. The key lies not in choosing between patching and compensating controls, but in understanding when each approach delivers optimal risk reduction within the unique constraints of automotive production.

As the fastest-growing malware hazard of the 21st century continues to threaten the uptime, profits and brand reputation of the automotive industry, the time for action is now. The next major automotive ransomware incident is not a matter of if, but when and the manufacturers who survive will be those who prepared with defense-in-depth strategies tailored to their operational realities.

Frenos helps automotive manufacturers identify and prioritize the most effective compensating controls for their specific OT environment, using AI-driven analysis to recommend alternative mitigation strategies that maintain both security and operational continuity. Our platform has been validated across multiple automotive facilities, reducing vulnerability exposure by an average of 89% without production impact. Visit frenos.io to learn more.

References

1. CrowdStrike. "NotPetya Ransomware Attack Technical Analysis." 2017.
2. Industrial Cyber. "Toyota supplier Denso, Bridgestone Americas targeted in ransomware attacks." 2022.
3. Control Engineering. "WannaCry ransomware takes Renault-Nissan plants offline." 2025.
4. CISA. "Petya Ransomware Alert TA17-181A." 2017.
5. Automotive Logistics. "Honda global operations hit by ransomware attack." 2020.
6. SOCRadar. "Major Cyber Attacks Targeting the Automotive Industry." 2024.
7. OTORIO. "Kia Ransomware and the Automotive Cyber Attacks Trend." 2021.
8. Threatpost. "Cybercriminals Batter Automakers With Ransomware, IP Theft Cyberattacks." 2021.