Your Understanding/Definition of Security
Core Definition: “The ability of a system to satisfy its goals in the presence of an adversary”
Three Critical Questions:
- What is the system? (Define boundaries, scope, context)
- What are the goals? (System goals vs. security goals)
- Who is the adversary? (Threat modeling)
Key Insight: Security is context-dependent - secure for whom, against what, for how long, and why
Your Understanding/Definition of Software Security
Software Security applies the same definition but focuses on:
- System: The software application and its operational environment
- Goals: Functional goals plus security properties (CIA model)
- Adversary: Those who can exploit software vulnerabilities
Security Components :
- Security Policies: High-level business-driven requirements
- Security Goals: What you want to achieve (confidentiality, integrity, availability)
- Security Mechanisms: How you achieve it (encryption, access control, backups)
Security as an afterthought.
CIA Model for Security Goals
- Confidentiality: Keeping secrets secret (passwords, personal data)
- Integrity: Ensuring only authorized changes (bank accounts, medical records)
- Availability: Timely access when needed (emergency systems, google (azure))
Your Take on Risk Analysis/Management
Simple Risk Assessment Framework :
Attack Difficulty vs Impact Matrix:
Low Medium High
Easy ✓ !!! !!!
Modest ✓ ✓ !!!
Difficult ✓ ✓ ✓
Risk Management Process :
- Understand business context
- Identify business and technical risks
- Synthesize and prioritize risks
- Define risk mitigation strategy
- Carry out fixes and validate
Key Principle: Start with high-risk threats (easy attacks with high impact)
Building Security In - Three Pillars
- Risk Management: Foundation for all security decisions
- Seven Touchpoints:
- Code review, Architectural review
- Penetration testing, Risk-based security testing
- Abuse cases, Security requirements, Security operations
- Knowledge: Stay informed about vulnerabilities, advisories, and best practices
Threat Modeling Manifesto
- What are we working on?
- What can go wrong?
- What are we going to do about it?
- Did we do a good enough job?
Remember: Security isn’t binary - it’s about managing risk within acceptable levels for your specific context and adversary model.