Threat Modelling Security In Agile

The word Agile is, sometimes used in a generic manner to denote any kind of “dynamic” or “unstructured” way of working with others. Commonly, this term suggests focused and rapidly iterative software process. Agile methodology is aimed to promote a more efficient, smooth-flowing and collaborative way of working to develop IT programs and computer software. However, as Agile prioritizes speed and adaptability, it is essential to incorporate a threat modelling methodology to proactively identify security risks and ensure robust application security throughout the development lifecycle. 

Today, the Agile method is simply called Agile, in which “A” symbolize symbolizes its “adherence” and has become widely accepted as an effective approach to project management within software development and testing groups. 

As the world is growing rapidly, the demands are also increasing. Today, there is a strong demand for rapid application delivery to manage today’s accelerating application development cycles. There are more applications like internet applications, mobile applications etc. But at the same time, keep an eye on the downside. Building your application very fast should not affect its security. To address this, threat modelling methodology plays a vital role in ensuring security remains a priority throughout the development process. 

Today, we are using multiple Agile methodologies. They include Scrum, XP (Extreme Programming) etc. You don’t have to focus on security just because you are using one of the agile methodologies, such as SDL, (SDL: you can understand in the next paragraph about SDL (You can learn more about SDL in the next paragraph) for Agile is now included in the Microsoft SDL process guidance. In this, you can find the latest details about the SDL. 

SDL is an acronym for Security Development Lifecycle. It is a software development process that helps the developers build more secure software. This also helps in addressing security compliance requirements which can reduce development cost, while developing the software. The core of SDL is incorporating threat modelling. 

What exactly is Threat Modelling?

Threat modelling is a process by which active threats can be identified and prioritized. These are prioritized according to the attacker’s point of view. The purpose of threat modelling is to provide defenders with a systematic investigation of the predictable attacker’s profile. Most likely, this model helps to identify the attack vectors (is a path by which attacker can gain a access to a System), and the assets most desired by an attacker.

“Trust” boundaries are the crux of threat modelling . Trust boundaries draw the demarcation lines between the parts of your application which are vulnerable. A simple example can explain it better. When you want to use an application and try to log in, then it is obvious that client is sending a message to the server. But if the perpetrator targets the application interface, then the entire information goes to that attacker and not to the server. The use of trust boundaries simplifies the identification and classification of threats in threat modeling.

A threat modelling methodology should ensure that the threat model is 100 percent complete before moving to the next phase of the software development cycle. The activities involved in the threat modelling methodology can be performed by any member of the project team, whether responsible for the entire project or a specific iteration. Additionally, team members should have a strong interest in security to effectively apply the threat modelling methodology and complete the threat model successfully. 

To become a project management expert, fulfill PRINCE2 Practitioner prerequisites and earn certification. Elevate your career by mastering efficient project management techniques. Enroll today!

Common Threat Modeling Methodologies 

​Integrating security into Agile development requires proactive threat identification and mitigation. Various threat modeling methodologies address this need, offering unique perspectives and techniques. Below are some of the most widely used methodologies: 

1. STRIDE 

Developed by Microsoft, STRIDE categorizes six types of security threats: 

• Spoofing Identity: Unauthorized use of another user’s credentials. 
• Tampering: Unauthorized data modification. 
• Repudiation: Actions that cannot be traced back to the perpetrator. 
• Information Disclosure: Exposure of sensitive information. 
• Denial of Service: Disrupting service availability. 
• Elevation of Privilege: Gaining unauthorized access. 

By analyzing each component against these threats, teams can identify vulnerabilities and implement countermeasures iteratively. 

2. PASTA (Process for Attack Simulation and Threat Analysis) 

PASTA is a risk-centric methodology with seven stages: 

• Define objectives 
• Establish technical scope 
• Decompose application components 
• Identify threats 
• Analyze vulnerabilities 
• Simulate attacks 
• Prioritize and mitigate risks 

PASTA ensures security is integrated throughout development, making it ideal for Agile teams. 

3. Attack Trees 

Attack Trees visually represent potential attack paths. Each node defines an attack vector, helping teams analyze and prioritize security risks systematically. This approach enhances collaboration and proactive mitigation.  

4. Trike 

Trike turns threat modeling into a risk management activity by defining acceptable risk levels. It integrates security requirements into Agile workflows, ensuring compliance with security benchmarks. 

5. VAST (Visual, Agile, and Simple Threat) 

Designed for large organizations, VAST differentiates between application and operational threat models. It supports Agile principles by enabling continuous threat modeling without disrupting development. 

6. OCTAVE (Operationally Critical Threat, Asset, and Vulnerability Evaluation) 

OCTAVE is a self-directed risk assessment methodology that identifies critical assets, evaluates vulnerabilities, and develops mitigation strategies, making it adaptable to Agile environments. 

7. DREAD 

DREAD is a quantitative risk model that evaluates threats based on: 

• Damage Potential 
• Reproducibility 
• Exploitability 
• Affected Users 
• Discoverability 

This structured scoring system helps prioritize threats based on risk level. 

8. CVSS (Common Vulnerability Scoring System) 

CVSS standardizes security vulnerability ratings by assessing attack complexity, authentication requirements, and impact on confidentiality, integrity, and availability. 

9. Hybrid Threat Modeling Method (hTMM) 

hTMM combines elements from different methodologies, allowing organizations to tailor threat modeling strategies to their specific security challenges. 

10. Security Cards 

Security Cards are a brainstorming tool that encourages teams to explore attack scenarios creatively. By considering adversary motivations, resources, and techniques, they help uncover non-traditional threats. 

How to Implement Threat Modeling in Agile Teams? 

Integrating threat modeling into Agile teams helps identify and mitigate security risks throughout the development lifecycle. Here’s how to implement it effectively: 

1. Integrate Threat Modeling into Agile Ceremonies 

Incorporate security discussions into Agile events: 

• Sprint Planning: Identify security concerns for upcoming user stories. 
• Backlog Refinement: Assess backlog items for security risks early. 
• Retrospectives: Review of past sprints to address security issues. 

This ensures continuous security focus without disrupting workflows. 

2. Adopt a 'Little and Often' Approach 

Instead of exhaustive analyses, conduct regular, focused threat modeling sessions: 

• Current Work Focus: Analyze user stories or features in small scopes. 
• Muscle Memory: Frequent practice builds proficiency in spotting threats. 

This iterative approach aligns well with Agile’s adaptability. 

3. Utilize Lightweight Threat Modeling Techniques 

Use simple methods to identify threats efficiently: 

• Evil User Stories: Explore how attackers might exploit vulnerabilities. 
• Security Cards: Engage teams in brainstorming potential risks. 

These techniques make security discussions accessible and engaging. 

4. Leverage Automated Tools 

Integrate security tools like Threagile, an open-source toolkit that automates risk assessments. Automation ensures consistent and efficient threat modeling. 

5. Foster a Security-First Culture 

• Training: Regular security awareness sessions. 
• Collaboration: Encourage open discussions on security concerns. 

A strong security culture makes threat modeling an integral Agile practice, ensuring secure and resilient software 

End Note 

Agile security is essential for balancing rapid development with robust protection. A well-defined threat modelling methodology plays a critical role in identifying and mitigating security risks early in the development lifecycle. By integrating security practices such as SDL and trust boundaries, Agile teams can proactively address vulnerabilities before they become critical issues. Adopting methodologies like STRIDE, PASTA, and Attack Trees within a structured threat modelling methodology helps teams assess and prioritize threats effectively. Implementing threat modelling methodology in Agile workflows ensures that security remains a continuous and collaborative effort. Ultimately, fostering a security-first mindset and leveraging automation tools will enable organizations to build resilient, secure, and high-performing software while maintaining Agile’s flexibility and speed.