1. CSCE 522 Secure Software Development Best Practices

2. CSCE 522 - Farkas2 Reading This lecture: Pfleeger Chapter 3.1 G. McGraw, Software [In]security: Software Security Zombies, 07/2011, http://www.cigital.com/resources/papers/ http://www.cigital.com/resources/papers/

3. CSCE 522 - Farkas3 How to address software security? Do not address at all Ad-hoc evaluation Add security features after the fact Identify security vulnerabilities Test security level Incorporate security throughout of SDLC

4. CSCE 522 - Farkas4 Checking for Known Vulnerabilities Need tool Possible attacks and attack types How the software behaves if something goes WRONG What motivates an attacker?

5. CSCE 522 - Farkas5 Three Pillars of Software Security Risk Management – Business case Software Security Touchpoints – Best practices Knowledge – Tools

6. CSCE 522 - Farkas6 Risk Management How much effort to invest in security Consequences of security breaches Acceptable-level of security Tracking and mitigating risk throughout the full SDLC

7. CSCE 522 - Farkas7 Knowledge Gathering, encapsulating, and sharing security knowledge Knowledge categories: – Prescriptive knowledge – Diagnostic knowledge – Historical knowledge Applied along the SDLC

8. CSCE 522 - Farkas8 Touchpoints System-wide activity: from design to testing and feedback Touchpoints: 1. Code review 2. Architectural risk analysis 3. Penetration testing 4. Risk-based security testing 5. Abuse cases 6. Security requirements 7. Security operations

9. CSCE 522 - Farkas9 Application of Touchpoints Requirement and Use cases Architecture and Design Test Plans Code Tests and Test Results Feedback from the Field 5. Abuse cases 6. Security Requirements 2. Risk Analysis External Review 4. Risk-Based Security Tests 1. Code Review (Tools) 2. Risk Analysis 3. Penetration Testing 7. Security Operations

10. CSCE 522 - Farkas10 Software Vendor Accountability Proper implementation of security features Looking for known security flaws Passing third party validation Source code analysis

11. CSCE 522 - Farkas11 Application of Touchpoints Requirement and Use cases Architecture and Design Test Plans Code Tests and Test Results Feedback from the Field 5. Abuse cases 6. Security Requirements 2. Risk Analysis External Review 4. Risk-Based Security Tests 1. Code Review (Tools) 2. Risk Analysis 3. Penetration Testing 7. Security Operations

12. CSCE 522 - Farkas12 Misuse Cases Software development: making software do something – Describe features and functions – Everything goes right Need: security, performance, reliability – Service level agreement – legal binding How to model non-normative behavior in use cases? – Think like a bad guy

13. CSCE 522 - Farkas13 Misuse Cases Extends use case diagrams Represent actions the system should prevent Represent together – Desired functionalities – Undesired actions Security: emergent property  must be built in from the ground up Making explicit trade offs

14. CSCE 522 - Farkas14 Misuse Cases Analyze system design and requirements – Assumptions – Failure of assumptions – Attack patterns Software that is used also going to be attacked What can a bad guy do and how to react to malicious use

15. CSCE 522 - Farkas15 Misuse Case Development Team work – software developers and security experts Identifying and documenting threats Creating anti-requirements: how the system can be abused Creating attack model – Select attack pattern relevant to the system – Include anyone who can gain access to the system

16. CSCE 522 - Farkas16 Application of Touchpoints Requirement and Use cases Architecture and Design Test Plans Code Tests and Test Results Feedback from the Field 5. Abuse cases 6. Security Requirements 2. Risk Analysis External Review 4. Risk-Based Security Tests 1. Code Review (Tools) 2. Risk Analysis 3. Penetration Testing 7. Security Operations

17. CSCE 522 - Farkas17 Software Testing Application fulfills functional requirements Dynamic, functional tests late in the SDLC Contextual information

18. CSCE 522 - Farkas18 Security Testing Test: finding flaws in software can be exploited by attackers Quality, reliability and security are tightly coupled Software behavior testing – Need: risk-based approach using system architecture information and attacker’s model

19. CSCE 522 - Farkas19 Security Testing Look for unexpected but intentional misuse of the system Must test for all potential misuse types using – Architectural risk analysis results – Abuse cases Verify that – All intended security features work (white hat) – Intentional attacks cannot compromise the system (black hat)

20. CSCE 522 - Farkas20 Penetration Testing Testing for negative – what must not exist in the system Difficult – how to prove “non-existence” If penetration testing does not find errors than – Can conclude that under the given circumstances no security faults occurred – Little assurance that application is immune to attacks Feel-good exercise

21. CSCE 522 - Farkas21 Penetration Testing Today Often performed Applied to finished products Outside  in approach Late SDLC activity Limitation: too little, too late

22. CSCE 522 - Farkas22 Late-Lifecycle Testing Limitations: – Design and coding errors are too late to discover – Higher cost than earlier designs-level detection – Options to remedy discovered flaws are constrained by both time and budget Advantages: evaluate the system in its final operating environment

23. CSCE 522 - Farkas23 Success of Penetration Testing Depends on skill, knowledge, and experience of the tester Important! Result interpretation Disadvantages of penetration testing: – Often used as an excuse to declare victory and go home – Everyone looks good after negative testing results

24. CSCE 522 - Farkas24 Behavior in the Presence of Malicious Attack What happens when the software fails? – Safety critical systems Track risk over time Security relative to – Information and services protected – Skills and resources of adversaries – Cost of protection System vulnerabilities

25. CSCE 522 - Farkas25 Malicious Input Software: takes input Trust input? – Malformed or malicious input may lead to security compromise – What is the input? Data vs. control Attacker toolkit

26. CSCE 522 - Farkas26 Traditional Software Development No information security consideration Highly distributed among business units Lack of understanding of technical security risks

27. CSCE 522 - Farkas27 Don’t stand so close to me Best Practices – Manageable number of simple activities – Should be applied throughout the software development process Problem: – Software developers: lack of security domain knowledge  limited to functional security – Information security professionals: lack of understanding software  limited to reactive security techniques

28. CSCE 522 - Farkas28 Vulnerability Monitoring Identify security weaknesses Methods: – Automated tools – Human walk-through – Surveillance – Audit – Background checks

29. CSCE 522 - Farkas29 Red Team Organized group of people attempting to penetrate the security safeguards of the system. Assess the security of the system  future improvement Requested or permitted by the owner to perform the assessment Wide coverage: computer systems, physical resources, programming languages, operational practices, etc.

30. CSCE 522 - Farkas30 Next Class Malicious code