Systems thinking is the ability to mentally “zoom out” to have the overview of what the entire system is doing, what its purpose is, how it interacts with and fits into the organization as a whole and other software used by the organization. It’s the whole question of what it does, why it does it, who it does it for, when and where it does it in the context of the entire collection, and how it does it in a generic sense.

A threat model is a tool that helps identify potential weaknesses. It's a place to start, not the whole thing.

Or What Makes A Software Tester Good?

Watch this awesome talk by Kate Paulk at TestBash Philadelphia 2017

Tips For The Lone Tester: Article 3 of 4

Tips For The Lone Tester: Article 1 of 4

Tips For The Lone Tester: Article 2 of 4

Tips For The Lone Tester: Article 4 of 4

How Kate Paulk stumbled into security testing.