Application Security: Model Trust and Protect Data

Threat modeling is a structured way to ask how a system could be misused or attacked.

An interactive concept flow for threat modeling starts with assets and boundaries, from its assumptions through the main operation and boundary checks.

Authentication answers who or what is making a request; authorization decides which actions that identity may perform on a resource.

Password storage should make a stolen database expensive to search.

Follow the key state changes and boundary checks involved in store password verifiers, not recoverable passwords.

Browser security depends on keeping untrusted data from becoming executable code or changing the meaning of a command.

An interactive concept flow for treat browser input as data at every boundary, from its assumptions through the main operation and boundary checks.

Trace untrusted input into a web page, identify the output context, and choose encoding or sanitization at the correct boundary.

Explain the model, execution steps, complexity, and limits of treat browser input as data at every boundary.