Threat modelling is a systematic approach to identifying, assessing, and mitigating security threats and vulnerabilities in a system, application, or process. It is a cornerstone of cybersecurity and software development, enabling organisations to proactively address potential risks before they are exploited. By understanding how attackers might target a system, threat modelling helps design effective countermeasures to protect valuable assets and ensure operational resilience.
The process begins with defining the scope and objectives, where the boundaries of the system under analysis are determined along with the security goals and stakeholder concerns. The next step involves identifying critical assets, such as sensitive data, intellectual property, or critical infrastructure that require protection. Once assets are identified, the system's architecture is analysed through diagrams or flowcharts to map data flows, interactions, and dependencies, often using tools like Data Flow Diagrams (DFDs).
Threat modelling includes systematically enumerating potential threats using frameworks like STRIDE (Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, and Elevation of Privilege) or DREAD (Damage, Reproducibility, Exploitability, Affected Users, and Discoverability). These frameworks help identify threats and pinpoint vulnerabilities in the system, such as insecure configurations, unpatched software, or poor access controls. Risks are then prioritised based on their likelihood and potential impact, often using a risk matrix, allowing organisations to focus resources on addressing the most critical threats.
To mitigate these risks, technical, administrative, or physical controls are proposed. Examples of such controls include encryption, firewalls, user authentication systems, and incident response plans. The effectiveness of these mitigations is validated, and the model is updated as systems evolve or new threats emerge, ensuring an iterative and adaptive approach to risk management.
Several methodologies support threat modelling. STRIDE and DREAD focus on categorising and scoring threats, while PASTA (Process for Attack Simulation and Threat Analysis) aligns business objectives with technical security requirements. Tools like Attack Trees visually map potential attack paths, and Kill Chain Analysis highlights stages of a cyberattack to identify preventive measures. The OWASP Threat Modelling Playbook offers guidance specifically for web applications and modern development practices.
The benefits of threat modelling are significant. It enables proactive risk management, helping organisations identify and mitigate risks early in the design or development lifecycle, reducing costs and improving security. By providing a deeper understanding of potential attack vectors, threat modelling enhances defences and supports compliance with security standards and regulations like GDPR, HIPAA, or ISO 27001. Threat modelling also facilitates collaboration between security, development, and business teams, improving communication and understanding of risks.
Despite its advantages, threat modelling comes with challenges. Large, interconnected systems can make comprehensive analysis complex, while the rapidly evolving threat landscape requires continuous updates to threat models. Resource constraints can make thorough threat modelling time-consuming, and gaps in expertise may hinder the process. Nonetheless, when conducted effectively, threat modelling strengthens an organisation’s security posture and helps protect its systems from evolving threats, making it an indispensable part of modern cybersecurity strategies.