5 April 2023
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Threat modelling is an essential process that every software development team should undertake to identify potential security risks and vulnerabilities in their systems. By using a structured approach to identify threats and countermeasures, developers can design more secure applications and reduce the risk of data breaches, unauthorized access, or other security incidents.
However, despite its importance, threat modelling is often overlooked or performed inadequately. In this guide, we will discuss the best practices for threat modelling and the common pitfalls that developers should avoid. We will also provide some code examples to illustrate how to implement threat modelling in your development process.
Best Practices for Threat Modelling:
1. Involve Security Experts: When designing your system, you should involve security experts to help identify potential threats and countermeasures. Security experts can provide valuable insights into security risks and help you to prioritize your efforts.
2. Identify Assets and Threat Actors: Start by identifying the assets that your system will store, process, or transmit. Then, identify the threat actors who may target those assets. Threat actors may include malicious insiders, external hackers, or other threat sources.
3. Use a Structured Approach: Use a structured approach to identify potential threats and countermeasures. The most common approach is to use a data flow diagram to map out the flow of data through your system. Then, use a threat modeling methodology such as STRIDE (Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege) to identify potential threats.
4. Evaluate Risks: Evaluate the risks associated with each potential threat. Consider the likelihood of the threat occurring, the impact it would have on your system, and the cost of implementing countermeasures.
5. Prioritize Countermeasures: Prioritize countermeasures based on the risks they mitigate and the cost of implementing them. Focus on the highest-priority threats first and implement the most effective countermeasures.
Common Pitfalls to Avoid:
1. Overlooking Threats: Developers often overlook potential threats, such as authentication bypass or injection attacks. Ensure that your team considers all potential threats and applies appropriate countermeasures.
2. Ignoring Security Throughout the Development Process: Threat modelling should not be a one-time event. It should be integrated into the development process to ensure that security is considered at every stage of development.
3. Failing to Evaluate Risks: Evaluating risks is essential to prioritizing countermeasures effectively. Don't skip this step or take it lightly.
4. Not Involving Security Experts: Security experts bring valuable insights and experience to the table. Make sure they are involved in the threat modelling process from the beginning.
Here are some examples of how to implement threat modelling in your development process.
Example 1: Using a Data Flow Diagram
In this example, we will use a data flow diagram to identify potential threats in a simple web application.
1. Create a data flow diagram that shows the flow of data through your application.
2. Identify the assets that your application stores, processes, or transmits, such as user data or sensitive information.
3. Identify the threat actors who may target those assets, such as external hackers or malicious insiders.
4. Use the STRIDE methodology to identify potential threats, such as SQL injection or cross-site scripting attacks.
5. Evaluate the risks associated with each potential threat and prioritize countermeasures accordingly.
Example 2: Threat Modelling in Agile Development
In an Agile development environment, threat modelling can be integrated into the development process as part of each sprint. Here's how:
1. During sprint planning, identify the features that will be developed during the sprint.
2. Use a data flow diagram to map out the flow of data through the feature and identify the assets and threat actors.
3. Use the STRIDE methodology to identify potential threats and evaluate the risks associated with each threat.
4. Prioritize countermeasures based on the risks they mitigate and the cost of implementing them.
5. Implement the countermeasures as part of the sprint and test them thoroughly.
Let's look at a few use cases where threat modelling can be applied.
Use Case 1: E-commerce Website
An e-commerce website stores sensitive information such as customer names, addresses, and payment information. Threat actors may include external hackers who try to steal this information or insiders who misuse their privileges to access customer data. Threat modelling can help to identify potential threats and prioritize countermeasures such as encryption, access control, and monitoring of privileged users.
Use Case 2: Healthcare Application
A healthcare application stores confidential patient information such as medical records and personal details. Threat actors may include external hackers who try to steal this information or insiders who misuse their privileges to access patient data. Threat modelling can help to identify potential threats and prioritize countermeasures such as secure authentication, data encryption, and strict access control policies.
Threat modelling is a crucial process that should be integrated into every software development team's workflow. By following the best practices and avoiding common pitfalls, developers can design more secure applications and reduce the risk of security incidents. Implementing threat modelling in your development process may require some effort upfront, but it will save time and costs in the long run by preventing security incidents and data breaches.
JBI Training is a leading provider of bespoke training courses in the field of cybersecurity, including threat modelling for developers. We offer a range of training options, including onsite and virtual training, tailored to meet the specific needs of organisations and individuals.
Our Cyber Security courses are designed to cover real-world scenarios for you and your staff, JBI Training's team of experienced instructors are experts in the field of cybersecurity, with many years of practical experience working in the industry. They use a variety of teaching methods, including hands-on exercises and case studies, to help participants develop practical skills and gain a deeper understanding of the material.
By partnering with JBI Training for your threat modelling training needs, you can ensure that your organisation is well-equipped to identify and mitigate security threats and protect against cyber-attacks. Our bespoke courses can be tailored to meet the specific needs of your organisation, ensuring that you get the most out of your training investment.
Microsoft's Threat Modeling Tool - A free tool that can be used to create threat models for software applications: https://learn.microsoft.com/en-us/azure/security/develop/threat-modeling-tool
OWASP Threat Modeling Guide - A comprehensive guide to threat modeling for web applications: https://owasp.org/www-community/Threat_Modeling
OpenSAMM - A framework for building and maintaining secure software: https://owasp.org/www-pdf-archive/SAMM_Core_V1-5_FINAL.pdf
These resources provide detailed information on threat modelling and related topics, such as risk assessment, mitigation strategies, and best practices for software development.!