What we will learn…

• What is Threat modeling?

• Threat modeling jargon - attack vectors, impact, severity, attack surface, and so on.

Threat Modeling

It’s simply a structured approach to pre-empt or identify risks that may exist in your system and you can build your security program around this instead of blindly following industry checklists. We try to answer questions such as what can go wrong, are we protected in that case, and how can we improve our security.

Our aim while building a threat model is to

• Identify, Enumerate and Prioritize security risks

• Identify Attack Vectors and Attack channels

• Identify likelihood of risks identified

• Identify controls and measures for addressing the risks

TM Jargon

1. Threat - Any potential danger or malicious action that can cause harm

2. Vulnerability - Any weakness that can be identified and exploited by a threat

3. Risk - Likelihood of the threat exploiting the vulnerability

4. Threat Actor - Agent that can identify and exploit the vulnerability

5. Threat Outcome - Result of a threat, C/I/A loss

6. Attack Surface - Self explanatory

7. Attack vector - Method/Technique used to perform an attack

Introduction of Vulnerabilities in our system

In a typical SDLC, if vulnerabilities are introduced during the initial design review phase is termed as a flaw.

The same vulnerabilities introduced in the Dev or deployment stage found are called Bugs.

Side note: As you can understand, findings issues as early as possible will save more money, time and effort. Threat modeling helps in exposing potential flaws in the early stages.

Impact and Likelihood

Our two favorite terms in cybersecurity!

Impact - Consequence of a threat identifying and exploiting a vulnerability (termed Severity as well)

Likelihood - Probability of a threat identifying and exploiting a vulnerability

Risk is typically calculated by an Impact vs Likelihood matrix.

Source: HBS

Risk helps with assessing potential damage and ways to manage it.

Risk Management

The 4 Ts of Risk management are:

1. Treat it - Mitigation

2. Terminate it - Removal of source of risk

3. Transfer it - Transference (Insurance/Contracts etc)

4. Tolerate it - Acceptance

Treating and Transferring Risks

• Preventive - Encryption, Access control etc.

• Detective - Logging and Monitoring

• Corrective - Backups

See you in the next one where we will talk about Trust Boundaries & Trust Zones.

Note: This threat modeling article series is a documentation of my learning from various sources including but not limited to AppSecEngineer, INE, OWASP, Youtube and more.