VisualPro Tech Brief
HARA and TARA at the Same Table
Why Integrated Safety-Security Analysis Is Becoming the Tool-Selection Criterion
Functional Safety (ISO 26262) × Cybersecurity (ISO/SAE 21434) | Industry Trend Brief
ISO 26262ISO/SAE 21434UN R155AIAG-VDAHARA · TARA
01Overview (TL;DR) — The Question Is Now “Does It Link?”
The era of functional safety (FuSa) and cybersecurity being run by separate teams, separate tools, and separate documents is ending. Across the industry, joint HARA·TARA workshops — where the same team performs ISO 26262 HARA (Hazard Analysis and Risk Assessment) and ISO/SAE 21434 TARA (Threat Analysis and Risk Assessment) together — are becoming standard practice. Safety hazards and security threats must be identified on the same item definition and the same architecture model, both to eliminate duplicated work and to catch security-induced safety risks.
In the same vein, SAE Mobility Engineering Technology (Tech Briefs) highlighted the pitfalls of running DFMEA, HARA, and FTA in isolation, and presented linked analysis as the remedy. The conclusions converge: integrated safety-security analysis has emerged as the key tool-selection requirement. VisualPro links FMEA, FTA, HARA, TARA, and STPA on a single platform and a single database.
Not a tool that does each analysis well — a tool that links the analyses.
02Why Now — Three Shifts Driving Safety-Security Integration
1Regulatory ConvergenceTwo mandatory assessments, one item
Since UN R155 (CSMS)/R156 took effect, type approval requires a cybersecurity management system, and both ISO 26262 and ISO/SAE 21434 require concept-phase risk assessments (HARA/TARA). The item and architecture under analysis are identical, but the analyses fork in two — done separately, you model the same system twice and document it twice.
2Process ConvergenceJoint HARA·TARA workshops
A hacked brake ECU is a security threat and a safety hazard at the same time. Joint workshops where safety and security experts share the item definition and cross-review scenarios remove duplication and capture cross-domain risks invisible to either analysis alone (attack → malfunction → injury). ASIL and CAL ratings come out of the same meeting record, keeping audit responses consistent.
3The Cost of SilosLinked DFMEA · HARA · FTA
The Tech Briefs article (Omnex) makes it plain — FMEA, FTA, and HARA all address product risk from different directions, and most organizations fail to ensure consistency across them, suffering inefficiency and missed risks. The recommended flow: HARA for hazard identification and classification, linked with top-down FTA and bottom-up DFMEA completing the same picture from opposite directions.
03Five Pitfalls of Disconnected Analyses
| Pitfall | What Happens When Disconnected | When Linked |
|---|
| Inconsistent severity ratings | HARA's S and DFMEA's S are rated independently — the same failure gets different grades; an audit finding | DFMEA inherits severity from HARA |
| Safety goals detached from failure analysis | FTA top events defined without reference to safety goals, weakening ASIL allocation evidence | Violation of a safety goal IS the FTA top event |
| Triple data entry | The same failure mode entered into HARA, FMEA, and FTA — wasted effort, version drift | Defined once, reused across all three |
| Unsynchronized changes | A design change updates one analysis; the others quietly go stale | All analyses synchronized in a single database |
| Security threats never reach safety | TARA attack paths are not propagated into safety analysis — security-induced safety risks are missed | HARA and TARA cross-reference the same model |
04How Linked Analysis Actually Works
| Method | Direction | Core Question | Deliverables | Link |
|---|
| HARA (ISO 26262) | Item level, top-down | What is hazardous? | Hazards, ASIL, safety goals | Safety goal → FTA top event / Severity → DFMEA |
| FTA | Top-down (effect → cause) | Why does it happen? | Fault logic tree, minimal cut sets | Basic events → DFMEA failure causes |
| DFMEA (AIAG-VDA) | Bottom-up (cause → effect) | How do we prevent it? | Failure modes, causes, S/O/D, AP | Effect severity inherited from HARA |
| TARA (ISO/SAE 21434) | Threat perspective | Who attacks, and how? | Threat scenarios, attack paths, CAL | Damage scenarios ↔ HARA hazards |
When the four analyses share the same item definition and the same system architecture (structure tree), these links stop being manual mappings and become database relations. That is what “linked analysis” actually means.
05How VisualPro Supports It
One Structure Tree, Five AnalysesJoint Workshop
FMEA, FTA, HARA, TARA, and STPA share the same system structure database. In a joint HARA·TARA workshop, safety and security teams analyze on the same model, on the same screen.
Cross-Analysis Traceability (Digital Thread)Traceability
Safety goal ↔ FTA top event ↔ DFMEA failure mode ↔ safety requirement, and TARA threat ↔ countermeasure are linked in a single database. Design changes and new threats propagate across the linked analyses, maintaining living traceability.
Standard-Conformant DeliverablesKR/EN Reports
AIAG-VDA FMEA, ISO 26262 HARA (ASIL), ISO/SAE 21434 TARA, and FTA in standard formats, with reports in Korean and English. Show the assessor clause-level evidence for every analysis.
MCP-Based AI Agent IntegrationAI Integration
MCP support for FMEA, FTA, HARA, TARA, and STPA lets AI agents such as Claude communicate directly with VisualPro — candidate hazard/threat identification through draft scoring performed conversationally, while the analyst focuses on verification and judgment.
06Frequently Asked Questions (FAQ)
Q1Do HARA and TARA really have to be done together?
The standards are separate (ISO 26262 / ISO/SAE 21434), but the item under analysis and the concept-phase timing are the same, and the results affect each other (security breach → safety hazard). A joint workshop is the most efficient way to eliminate duplicate modeling and capture cross-domain risks — and it is becoming established industry practice.
Q2We already run each analysis well in Excel. Why an integrated tool?
The problem is not the quality of each analysis but the consistency between them. Severity mismatches, triple data entry, and unsynchronized changes are structural in file-based work, and audit traceability demands (which safety goal is verified by which failure analysis) are practically impossible to maintain through manual links between spreadsheet files.
Q3Which comes first, FTA or FMEA?
Linkage matters more than order. Establish hazards and safety goals with HARA, expand safety-goal violations top-down with FTA to understand the causal structure, then quantify bottom-up at the cause level with DFMEA (S/O/D, AP). The two methods complete the same picture from opposite directions.
07Start Now (Next Step)
Integrated safety-security analysis is no longer a best-practice showcase — it is the baseline that audits and contracts demand. Start your next joint HARA·TARA workshop on a single platform with VisualPro, proven in automotive, defense, robotics, and semiconductor programs.
Share the structure, link the analyses — integrated safety-security design with VisualPro.
Reference: SAE Mobility Engineering Technology / Tech Briefs, “Avoiding Risk Analysis Pitfalls: Implementing Linked DFMEA, HARA, and FTA” (Omnex)
VisualPro & Demo Inquiries
The era of functional safety (FuSa) and cybersecurity being run by separate teams, separate tools, and separate documents is ending. Across the industry, joint HARA·TARA workshops — where the same team performs ISO 26262 HARA (Hazard Analysis and Risk Assessment) and ISO/SAE 21434 TARA (Threat Analysis and Risk Assessment) together — are becoming standard practice. Safety hazards and security threats must be identified on the same item definition and the same architecture model, both to eliminate duplicated work and to catch security-induced safety risks.
In the same vein, SAE Mobility Engineering Technology (Tech Briefs) highlighted the pitfalls of running DFMEA, HARA, and FTA in isolation, and presented linked analysis as the remedy. The conclusions converge: integrated safety-security analysis has emerged as the key tool-selection requirement. VisualPro links FMEA, FTA, HARA, TARA, and STPA on a single platform and a single database.
Integrated safety-security analysis is no longer a best-practice showcase — it is the baseline that audits and contracts demand. Start your next joint HARA·TARA workshop on a single platform with VisualPro, proven in automotive, defense, robotics, and semiconductor programs.