Threat Modelling using Architecture, Threats, Attack Surfaces, and Mitigations (ATASM)

Last week I gave a presentation on threat modelling to the Azure Security meetup forum in Melbourne. After such a challenging 2020 and the subsequent halt to most in-person events, it was great to be back and talking security with like-minded professionals in the field.

In the interest of spreading knowledge and giving back to the community, I am uploading my presentation to my website here so that it can be downloaded and referenced by anyone who may be interested in performing threat modelling using the ATASM approach detailed in this presentation.

While the presentation covers a great deal of information around ATASM and its usage, there are some additional points I’d like to mention here.

• Threat Modelling is a process that is best performed in the early stages of any technical solution design. Often it is in these early design stages of a project where the logical and component-level architecture contains weaknesses and gaps in security. Threat modelling is the process of identifying these control gaps and ensures a more secure system overall.

• There is no one single method that trumps all when it comes to threat modelling. The ATASM model is just one of the many approaches available. The goals and objectives for performing threat modelling can differ in most cases and depending on those unique requirements, you can (and should) adjust your threat modelling approach in order to best meet your objectives.

• The goal of any threat modelling exercise is mainly to understand the real threats to the business and the assets that are most at risk of being attacked.

• Security controls are expensive, this is a fact. We can’t just put a bunch of security controls everywhere within our environment to stop every possible threat. So by better understanding our high-value, high-risk systems, we can provide an effective level of security using controls that can be justified according to the risk appetite of the business.

Lastly, for a more comprehensive deep dive on security architecture and threat modelling using the ATASM approach, I recommend reading the book “Securing Systems: Applied Security Architecture and Threat Models” by Brook S. E. Schoenfield.