Threat Model for Roadworks: Attack Scenarios Against Smart Highway Projects

Hook: Why transportation teams must treat smart highways as high-value cyber-physical targets now

State DOTs, contractors, and IT/OT teams planning multi-billion-dollar highway modernization projects—like Georgia’s 2026 push to expand I‑75—face an urgent, practical problem: modern highways are not just concrete and asphalt anymore. They’re distributed cyber-physical systems that combine tolling, traffic management, roadside sensors, edge compute, and contractor corporate networks. That convergence creates a broad attack surface that can be exploited to cause congestion, safety incidents, fiscal loss, regulatory liability, and reputational damage. This article gives security teams a usable threat model catalog for large smart-highway projects, prioritized mitigations, and a postgraduate-level incident root-cause playbook tuned for 2026 realities.

The 2026 context: trends driving new risk profiles

By early 2026, three trends reshape how adversaries target transportation modernization projects:

• Commoditized ransomware and extortion services—ransomware groups have matured their playbooks for targeting contractors and MSPs responsible for critical infrastructure, increasing double-extortion and leak-site pressure.
• Supply-chain weaponization—attacks on CI/CD pipelines, firmware update processes, and third-party components remain effective, as demonstrated since SolarWinds and reinforced by multiple late‑2025 vendor compromise disclosures that impacted service providers.
• Sensor and positioning spoofing—advances in low-cost GNSS spoofers, RF signal generators, and adversarial ML attacks against vision systems make roadside sensor spoofing practical at scale, enabling physical disruption without direct access to control networks.

How to use this threat model catalog

This catalog is designed for risk assessments, tabletop exercises, and incident response playbooks. For each attack scenario we present: attacker motivation, attack vectors, targeted assets, likely impact, indicators of compromise (IOCs), recommended mitigations, and root-cause analysis steps.

Catalog overview — prioritized attack scenarios

1. Supply-chain compromise of roadside hardware/software
2. Ransomware on contractor and MSP networks
3. Physical-sensor spoofing and data integrity attacks
4. Compromise of tolling/payment systems
5. OT lateral movement and traffic-control manipulation
6. Insider-enabled sabotage during construction or maintenance

1) Supply-chain compromise of roadside hardware/software

Attacker motivation

Long-term persistence, espionage, pre-positioning for future disruptive operations, or to insert clandestine backdoors enabling large-scale disruption during peak travel periods.

Attack vectors

• Compromised firmware or signed binaries distributed through vendor updates.
• Trojanized SDKs and libraries used by ITS software vendors.
• Compromise of build servers (CI/CD) for supplier software.

Targeted assets

• Roadside units (RSUs), cameras, LIDAR/radar processors, tolling gateways, edge compute modules.
• Central traffic management software, vendor management portals.

Likely impact

Stealthy data manipulation, large-scale sensor suppression, remote code execution in edge nodes, or scheduled mass disruption timed to major traffic events.

IOCs and detection

• Unexpected new firmware versions or code signatures on edge devices.
• Anomalous communication from RSUs to unknown infrastructure or cloud endpoints.
• Build pipelines showing unexpected dependency changes or commit signatures.

Mitigations

• Require vendor SBOMs, signed updates, and reproducible builds for all ITS components.
• Implement code-signing verification and secure boot on edge hardware.
• Enforce strict supplier risk management—periodic audits, penetration testing, and incident reporting clauses in contracts.

Root-cause analysis checklist

1. Collect firmware images and verify signatures.
2. Forensically preserve build servers and VCS logs.
3. Map supply-chain provenance to identify compromise origin and downstream distribution scope.

2) Ransomware on contractor and MSP networks

Attacker motivation

Financial gain through encryption and double extortion; tactical leverage by threatening to leak design or operational data that could endanger public safety or delay project milestones.

Attack vectors

• Phishing, credential stuffing, or exploiting exposed RDP/VPN endpoints on contractor networks.
• Supply-chain compromise where MSPs push malicious updates to multiple clients at once (Kaseya-style patterns).

Targeted assets

• Contractor project management systems, design repositories, cloud storage with traffic models, payroll and billing systems tied to procurement and payments.
• Remote maintenance tools with privileged access to OT environments.

Likely impact

Operational delays, withheld invoices and payments, forced manual operations for tolling or traffic control, regulatory breach notifications, and public trust erosion.

IOCs and detection

• Unusual encryption activity on file shares or backup failures.
• New processes spawning en masse on contractor endpoints.
• Threat actor leak sites or extortion communications mentioning project data.

Mitigations

• Enforce strict network segmentation and least privilege between corporate networks and OT/ITS networks.
• Mandate multi-factor authentication, EDR with rollback capability, and immutable backups with offline air-gapped snapshots.
• Contractually require suppliers to maintain incident response plans and cyber liability insurance.

Root-cause analysis checklist

1. Preserve affected endpoints and network flows; collect memory for forensic analysis.
2. Trace initial access vectors—phishing emails, exposed services, or third-party credential theft.
3. Assess data exfiltration scope and begin notification workflows for regulators and stakeholders.

3) Physical-sensor spoofing and data integrity attacks

Attacker motivation

Create real-world disruption—traffic jams, accidents, false congestion statistics—or manipulate dynamic tolling to cause financial loss or favor specific routes.

Attack vectors

• GNSS/GPS spoofing to mislead location-based services (toll cameras, vehicle-infrastructure coordination).
• RF jamming or replay attacks against wireless sensors, DSRC/C-V2X, or roadside wireless links.
• Adversarial inputs against camera/vision ML—projected patterns or adversarial stickers to misclassify vehicles or lanes.

Targeted assets

• Vehicle detection loops, inductive sensors, radar/LIDAR arrays, camera feeds, GNSS-dependent timing and positioning services.

Likely impact

False positives/negatives in incident detection, unsafe signal timings, unintended lane closures, cascading congestion, and potential for accidents in worst-case scenarios.

IOCs and detection

• Discrepancies across sensor fusion outputs (e.g., radar shows vehicles where cameras show none).
• GNSS anomalies: sudden shifts in position reports, loss of satellite visibility, or inconsistent timing across devices.
• Patterned, repeatable image perturbations or RF interference detected by spectrum monitors.

Mitigations

• Adopt multi-sensor fusion and cross-checks; require divergence thresholds and fail-safe modes that default to conservative signaling.
• Harden positioning with multi-constellation GNSS, inertial navigation backups, and GNSS authentication where available.
• Deploy RF spectrum monitoring and geofenced alerts for GNSS anomalies; enforce tamper-evident hardware and physical security for roadside sensors.

Root-cause analysis checklist

1. Compare raw sensor streams across systems; preserve video, radar, and RF logs.
2. Use sensor replay and controlled testing to reproduce spoofing signatures.
3. Examine physical access logs and maintenance records for tamper indicators.

4) Compromise of tolling/payment systems

Attacker motivation

Monetary theft, fraudulent toll credits, and reputation damage—attackers can also weaponize transaction delays to create economic pressure.

Attack vectors

• API abuses, credential stuffing, or vulnerabilities in payment components.
• Third-party payment processors or back-end reconciliation systems with inadequate controls.

Mitigations

• Tokenize payment data, segregate payment processing from operational networks, and enforce PCI DSS compliance for all payment-facing systems.
• Monitor reconciliation anomalies, implement real-time fraud detection, and ensure strong attestations for any vendor-integrated payment services.

5) OT lateral movement and traffic-control manipulation

Attacker motivation and impact

Physical harm: changing signal timings to cause collisions, disabling lanes and message signs, or corrupting traffic models to force gridlock.

Attack vectors and mitigations

• Pivot paths often begin on contractor remote access tools; mitigate with strict privileged access management, jump hosts, and MFA.
• Enforce network microsegmentation, whitelist authoritative control-plane endpoints, and deploy behavioral OT anomaly detection.

6) Insider-enabled sabotage during construction or maintenance

Insiders—disgruntled employees or coerced contractors—can bypass technical controls through legitimate credentials, physical tampering, or by introducing malicious components. Address this with robust background checks, least privilege, and rigorous change-control processes that require dual approvals and out-of-band verification for any critical configuration changes.

Detection, incident response, and root-cause playbook

When an incident occurs, transportation teams must move faster than public scrutiny. Here’s a compact operational playbook tuned to smart-highway projects.

Immediate actions (first 0–4 hours)

• Activate the incident response team and executive crisis cell.
• Isolate affected segments: remove compromised devices from networks, implement ACLs, and block known malicious endpoints.
• Preserve evidence: collect memory, logs, firmware images, and secure chain-of-custody.

Containment and eradication (4–72 hours)

• Engage vendors and legal counsel early; notify regulators per contractual and legal requirements.
• Apply hotfixes and cryptographic verification of firmware and images before redeploying devices.
• Restore from immutable backups where necessary; validate with integrity checks.

Recovery and validation (72 hours–weeks)

• Perform staged return-to-service with continuous monitoring and threat-hunting sweeps.
• Run penetration tests and red-team exercises to confirm the threat actor has been removed.
• Rebuild trust in data feeds with calibration tests and controlled sensor recomparison.

Post-incident root-cause analysis and lessons learned

1. Conduct a formal RCA that combines digital forensics with physical inspections and vendor audits.
2. Use the 5‑why method coupled with evidence mapping to trace to systemic failures (policy, tooling, vendor controls, or human error).
3. Publish redacted findings where possible to improve industry awareness and update contracts and SLAs.

Note: Effective RCA for smart highways must merge IT, OT, supply-chain, and physical forensics. Each domain’s evidence informs the other.

Controls prioritized for highway modernization projects (practical roadmap)

Budget cycles for projects like Georgia’s I‑75 expansion must include security controls. Prioritize the list below in procurement and design phases.

1. Supply-chain hygiene: SBOMs, signed updates, vendor attestation, and periodic third-party audits.
2. Network segmentation: Enforce strict separation between contractor corporate, cloud, and OT/ITS networks using VLANs, firewalls, and microsegmentation.
3. Device security: Secure boot, TPM-based attestation, endpoint protection for edge devices, and tamper-evident enclosures.
4. Identity and access: MFA, ephemeral admin sessions (PAM), least privilege for remote maintenance tools.
5. Telemetry and anomaly detection: Multimodal sensors, spectrum monitoring, and AI-driven anomaly detection tuned to traffic baselines.
6. Resilience and backups: Immutable backups, air-gapped snapshots, and runbook-tested failover modes.
7. Legal and contractual safeguards: Incident response SLAs, breach disclosure timelines, and cyber insurance aligned to infrastructure risk.

Case study snippets: learning from precedent

Lessons are drawn from multiple high-profile incidents that reshaped how infrastructure programs approach security:

• Ransomware against pipelines and MSPs taught industry to distrust perimeter-only defenses and to require immutable backups and rapid containment capabilities.
• Supply-chain compromises like SolarWinds highlighted the risk of trusted vendor updates and the importance of build-pipeline integrity and SBOM visibility.
• ICS-targeted malware (TRITON-like) underscored that OT devices need behavior-focused monitoring and safe fail-to-safe designs.

Practical checklist for program managers before procurement

• Include security requirements in RFPs: SBOM, secure firmware updates, attestation capabilities, and incident notification timelines.
• Require suppliers to provide third-party penetration test reports and an IR playbook specific to transportation systems.
• Allocate a security contingency fund (typically 3–7% of project IT/OT spend) for continuous monitoring and remediation.
• Plan for cross-functional governance: integrate cybersecurity into design reviews, construction checklists, and operational handoffs.

Future predictions through 2028 — what teams should prepare for now

• Increased adversary sophistication: Attackers will combine supply-chain insertion with sensor spoofing to create multi-vector, synchronized incidents.
• Regulatory tightening: Expect state and federal mandates requiring SBOMs and incident reporting for transportation projects.
• Tooling advances: Wider adoption of hardware attestation, secure element provisioning, and cryptographic time services will provide better defenses if embraced early.

Actionable takeaways

• Begin threat modeling now: perform scenario-based exercises that include supplier compromise and sensor spoofing scenarios.
• Require SBOMs and signed firmware for all roadside devices and validate update mechanisms during acceptance testing.
• Harden contractor access: use PAM, ephemeral credentials, and segmented remote access gateways for maintenance.
• Design sensor fusion and fail-safe behaviors so systems default to safe modes on divergence or GNSS anomalies.
• Prepare an IR roster that includes legal, communications, vendors, and public safety partners; rehearse tabletop exercises annually.

Closing: why a threat model catalog matters for every highway program

Large-scale highway modernization projects are attractive targets because they combine high public impact, complex supply chains, and a mix of legacy and modern control systems. A focused threat model catalog gives program owners and security teams a repeatable way to identify high-risk attack paths, prioritize mitigations tied to real-world attacker motivations, and shorten the time from detection to safe recovery. As the Georgia I‑75 program and similar state projects move into construction and integration in 2026, embedding these controls into procurement, engineering, and operations will materially reduce risk.

Call to action

If you manage or supply smart-highway systems, start with a threat-model workshop this quarter. Book a cross-functional tabletop, require SBOMs in your next procurement, and implement a segmented, monitored architecture before you flip the first roadside switch. Contact incidents.biz for a tailored threat-model session and an incident-readiness assessment built for transportation modernization programs.

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