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The Information Systems Group, Dept of Information Science and Media Studies, Univ of Bergen

Misuse Cases

A technique for early elicitation of security-related threats and requirements to information systems

Misuse case analysis was proposed for early elicitation and specification of security threats and requirements. The technique contains diagrams and textual specifications that are variants of the better known use cases, except that misuse cases specify behaviour that is not wanted in the proposed system, such as malicious attacks. The main idea is to capture security issues early in the project and to make it easier for participants to think clearly and openly about security threats by taking the perspective of the attacker and visualising how (positive) use cases and (negative) misuse cases are related. Misuse cases is a lightweight option for projects where there is not sufficient time or competence to apply more formal techniques, but it can also be used as an informal front-end to more elaborate techniques.

The essential elements of the Misuse Case technique are:

• A diagram notation where misuse cases and their malicious actors can be shown together with regular use cases and actors. Relationships in the diagram show how misuse cases threaten legitimate use cases and how security use cases mitigate misuse cases.
• A set of textual templates for describing misuse cases. As argued in [8], use case diagrams often just give a shallow overview. Textual descriptions that contain scenario paths are therefore needed to really understand what the user wants to do. Similarly, textual misuse cases may show in more detail what an attacker might try to do.

Main researchers:

• Professor Guttorm Sindre, IDI, NTNU, Trondheim
• Professor Andreas L. Opdahl, Infomedia, UiB, Bergen