Designing secure software is an increasingly hot topic, and for good reason. In recent weeks, we’ve seen a global effort from governments and cybersecurity agencies to encourage security by design through new guidance and changes to procurement rules. During the G7 in May, the QUAD nations (Australia, India, Japan and the United States) released a set of Joint Principles for Secure Software. In the U.S., there are even plans for legislation to make software makers liable for the security of their products. The need for software to be made secure at the design phase has been spotlighted further by recent cybersecurity incidents such as the hack by ransomware group CLOP that exploited flaws in MOVEit software.

But secure design is not a part of every developer’s skill set, and it’s not on the syllabus of every coding course. If you’re brilliant at writing code and keen to know more about how you make that code secure, where do you start?

Here are five tips from former DevSecOps and threat modeling engineer Fraser Scott, now IriusRisk’s VP of product:

1. Get to Know the Threats

To be able to design secure software effectively, you need to understand the threats. A great starting point is the OWASP Top 10. OWASP aims to identify the most critical security risks to web applications. Top of that list is broken access control, and insecure design itself sits at number four. Understanding the biggest risks is the first step towards mitigating them in software development.

2. Try Threat Modeling

The foundation of secure design is threat modeling, which is the process of identifying and mitigating plausible security threats. In its simplest form, this is about looking at your software design and asking Adam Shostack’s four questions:

1. What are we working on?
2. What can go wrong?
3. What are we going to do about it?
4. Did we do a good enough job?

The OWASP Top 10 gives you a sense of what the risks might be, and threat modeling is the process of identifying them in your design. See if any of those top ten risks might impact your design, consider what could go wrong and work out what you can do to mitigate it. Before you start writing any code, consider whether you’ve done a good enough job to make the software secure. The sooner you find design issues, the cheaper and easier they are to fix.

3. Connect With a Community

There are plenty of communities of people out there grappling with the same challenges that you are. Experts in security and threat modeling and developers are coming together to discuss and try to solve some of the key challenges in secure design. One such community is Threat Modeling Connect, where people use the forum to share ideas and discuss issues. Experts also host webinars and write blogs. The community also held its first-ever conference in October. There is also a community dedicated to threat modeling on Reddit, and the OWASP Slack has a #threat-modeling channel.

4. Experiment With Automation

Companies who are developing software on a large scale use tools to automate the threat modeling process. IriusRisk makes a community edition of its automation tool available for free, for life, to people who want to give threat modeling a try. As someone who is starting out in secure design, using a tool like this, which generates many of the relevant threats and countermeasures for you, is a great way to experiment with your first threat models. And we’re not the only ones; you can also use the OWASP Threat Dragon and Microsoft’s Threat Modeling for free.

5. Build a Library of Secure Code

One shortcut to secure design is using existing secure design patterns and road-tested components. As you develop software, keep a library of secure code that has been threat-modeled and scanned using application security testing tools that you can return to in the future. The Threat Model Cookbook on Git Hub has some sample threat models you can use as a starting point.