# Threat Analysis and Risk Assessment of a Driver Monitoring System
## 6 Risk Analysis
### STRIDE Application to System Components  
Before analyzing the risks in detail, it is crucial to assess the safety impact of the identified threats. This analysis focuses on evaluating how different threats could affect the safety of the vehicle occupants, as the most critical factor in any DMS is the protection of the driver and passengers. The safety impact is categorized into different levels, from critical to negligible, depending on the potential consequences of each threat.  
In our analysis, we found that the most significant safety threats stem from Spoofing, Tampering, and Elevation of Privilege attacks. These threats, if not mitigated, could lead to hazardous driving conditions, incorrect system behavior, or even complete system failure.  
Table 3 presents an overview of the safety impact of potential failures across key components of the DMS, structured according to the _STRIDE_ framework. The table categorizes each component's susceptibility to Spoofing (S), Tampering (T), Repudiation (R), Information Disclosure (I), Denial of Service (D), and Elevation of Privilege (E), assessing the severity of each safety impact.  
The color-coded classification represents the level of safety impact:  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Threat Type** & **Low Risk** & **Medium Risk** & **High Risk** & **Total** \\ \hline Spoofing & 5 & 1 & 3 & 9 \\ \hline Tampering & 24 & 7 & 0 & 31 \\ \hline Repudiation & 8 & 1 & 0 & 9 \\ \hline Information Disclosure & 30 & 1 & 0 & 31 \\ Denial of Service & 27 & 3 & 1 & 31 \\ \hline Elevation of Privilege & 1 & 3 & 0 & 4 \\ \hline Total & 95 & 16 & 4 & 115 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Distribution of threats by STRIDE and risk level.  
* **Search**: Failures that pose a direct and significant safety risk, potentially leading to system failure or hazardous driving conditions;
* **Major**: Failures that degrade system performance and could contribute to unsafe conditions under specific scenarios;
* **Moderate**: Failures that affect system functionality but have limited direct safety consequences;
* **Search**: Failures that have minimal or no meaningful safety impact.  
Key findings from the safety impact table:  
* The Calculation Unit (CU) exhibits the highest criticality, with Severe (Red) safety impacts in multiple STRIDE categories. This underscores its central role in processing sensor data and issuing control commands;
* The Camera Sensor (CS) and Camera Activator (CA) are primarily affected by _Major (Orange) and Severe (Red) risks_, reflecting their importance in driver monitoring and potential vulnerability to incorrect or delayed image processing;
* Warning devices (WD1 and WD2) are largely categorized under Negligible (Green) or Moderate (Yellow) impacts, indicating that while failures may reduce system effectiveness, they do not directly compromise vehicle safety;
* Data integrity threats, such as Tampering (T) and Information Disclosure (I), generally have lower safety impacts but may still influence the reliability of safety-critical decisions;
* Denial of Service (D) failures, particularly for the Calculation Unit and Vehicle Status Analysis, are Severe (Red) or Moderate (Yellow), highlighting their potential to disrupt real-time monitoring and intervention.  
This analysis provides a structured safety impact assessment of DMS vulnerabilities, guiding the prioritization of fault tolerance mechanisms, redundancy strategies, and real-time monitoring enhancements to mitigate high-risk failures effectively.  
The application of the STRIDE framework to the DMS architecture provides a systematic method for identifying potential threats and evaluating the effectiveness of security measures. This chapter analyzes critical components of the DMS--including sensors, calculation units, communication interfaces, and actuators--and assesses vulnerabilities using the STRIDE model.