Threat ModellingFour questions that surface most design-level security problems.ComputingAdapted from the standard four-question frame.1What are we building?Draw the data flow. Every arrow crossing a trust boundary matters.2What can go wrong?Walk STRIDE: spoofing, tampering, repudiation, disclosure, denialof service, elevation.3What are we doing about it?For each risk: mitigate, transfer, accept or eliminate. Write downwhich.4Did we do a good job?Revisit when the design changes. A threat model is a document,not an event.TRUST BOUNDARIESBrowser → serverService → serviceApplication → databaseAnything crossing an organisational edgeMost breaches exploit a design decision, not a coding bug. Design isthe cheapest place to find them.Threat Modellinglearnposters.com
Threat Modelling — printable computing wall chart from LearnPosters. Free vector PDF, US Letter and A4.

Threat Modelling, step by step

Adapted from the standard four-question frame.

  1. What are we building?Draw the data flow. Every arrow crossing a trust boundary matters.
  2. What can go wrong?Walk STRIDE: spoofing, tampering, repudiation, disclosure, denial of service, elevation.
  3. What are we doing about it?For each risk: mitigate, transfer, accept or eliminate. Write down which.
  4. Did we do a good job?Revisit when the design changes. A threat model is a document, not an event.

Trust boundaries

  • Browser → server
  • Service → service
  • Application → database
  • Anything crossing an organisational edge

Most breaches exploit a design decision, not a coding bug. Design is the cheapest place to find them.

Questions about the Threat Modelling poster

What’s on the Threat Modelling poster?
4 numbered steps, with a full worked run-through. Adapted from the standard four-question frame. What are we building? — Draw the data flow. Every arrow crossing a trust boundary mat…; What can go wrong? — Walk STRIDE: spoofing, tampering, repudiation, disclosure, denia…; What are we doing about it? — For each risk: mitigate, transfer, accept or eliminate.…; Did we do a good job? — Revisit when the design changes. A threat model is a document…. Most breaches exploit a design decision, not a coding bug. Design is the cheapest place to find them.
Who is the Threat Modelling poster for?
Threat Modelling belongs to the Computing section rather than to a school year, because computing is not something one grade owns. Anyone learning security can pin it up — a beginner, a student mid-course, or someone revising years later.
When should you use the Threat Modelling poster?
Do this on a whiteboard before writing code. It is the cheapest security work there is. A wall chart earns its place by being glanceable from where the work is happening, so Threat Modelling belongs on the wall where that computing work actually happens, within glancing distance, rather than filed away.
What other posters go with Threat Modelling?
Secrets, AuthN vs AuthZ and Hashing vs Encryption sit alongside Threat Modelling in the Computing section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.SecretsAuthN vs AuthZHashing vs Encryption
Is the Threat Modelling poster free to download and print?
Yes. Threat Modelling downloads as a free PDF with no account, no email and no watermark, like everything else in the Computing section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
What size does the Threat Modelling poster print at?
Threat Modelling is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Threat Modelling loses nothing.Printing guide

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