CSCE 522 Secure Software Development Best Practices

1. CSCE 522 Secure Software DevelopmentBest Practices

2. Reading • This lecture: • Pfleeger Chapter 3 • G. McGraw, Software [In]security: Software Security Zombies, 07/2011, http://www.cigital.com/resources/papers/

3. 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 CSCE 522 - Farkas 3

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

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

6. 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 CSCE 522 - Farkas 6

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

8. Touchpoints • System-wide activity: from design to testing and feedback • Touchpoints: • Code review • Architectural risk analysis • Penetration testing • Risk-based security testing • Abuse cases • Security requirements • Security operations CSCE 522 - Farkas 8

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

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

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

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

17. Software Testing • Application fulfills functional requirements • Dynamic, functional tests late in the SDLC • Contextual information

18. 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. 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. 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. Penetration Testing Today • Often performed • Applied to finished products • Outside  in approach • Late SDLC activity • Limitation: too little, too late

22. 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. 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. 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. 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. Traditional Software Development • No information security consideration • Highly distributed among business units • Lack of understanding of technical security risks

27. 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. Vulnerability Monitoring • Identify security weaknesses • Methods: • Automated tools • Human walk-through • Surveillance • Audit • Background checks

29. 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. Next Class • Reading Assignment: Textbook Ch. 3.2 malicious code • Network Security