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CIT 380: Securing Computer Systems

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  1. CIT 380: Securing Computer Systems Policies CIT 380: Securing Computer Systems

  2. Why Policies? • People are often the security problem. CIT 380: Securing Computer Systems

  3. NKU Password Policy • https://www.nku.edu/password/index.php CIT 380: Securing Computer Systems

  4. NKU Acceptable Use Policy for Technology Resources • http://it.nku.edu/itsecurity/docs/acceptableusepolicy.pdf CIT 380: Securing Computer Systems

  5. Types of Security (CIA) • Confidentiality • Integrity • Availability CIT 380: Securing Computer Systems

  6. Confidentiality • Keeping information secret • Bank records • Medical records • Student records • Personally identifiable information CIT 380: Securing Computer Systems

  7. Integrity • Accuracy and reliability of information • You are charged correctly for a purchase • Your bank balance is correct • You register for the correct class CIT 380: Securing Computer Systems

  8. Availability • Reliable and timely access • Email is accessible • Can access airline reservation system CIT 380: Securing Computer Systems

  9. Which is most important? • National Defense • Confidentiality • Banking • Integrity CIT 380: Securing Computer Systems

  10. Security Planning • Planning to address security needs. • Risk assessment. • Crafting policies to reflect risks and needs. • Implementing security. • Audit and incident response. CIT 380: Securing Computer Systems

  11. Trust • Security professionals generally don’t refer to a computer system as being “secure” or “unsecure.” • Trust – level of confidence that a computer system will behave as expected. CIT 380: Securing Computer Systems

  12. Risk Assessment • Identify assets and their value • Identify risk to assets • Calculate risk CIT 380: Securing Computer Systems

  13. Risk Assessment • What assets are you trying to protect? • What are the risks to those assets? • How well does each potential security solution mitigate those risks? • What other risks does the security solutions impose on me? • What costs and trade-offs do the security solutions create? CIT 380: Securing Computer Systems

  14. Identify Assets? • Home computer system • E-commerce web server CIT 380: Securing Computer Systems

  15. Tangibles Computers Data Backups Printouts Software media HR records Intangibles Privacy Passwords Reputation Goodwill Performance Identifying Assets CIT 380: Securing Computer Systems

  16. Identify Risk? • Home computer system • E-commerce web server CIT 380: Securing Computer Systems

  17. Identifying Risks • Loss of key personnel • Loss of key vendor or service provider • Loss of power • Loss of phone / network • Theft of laptops, USB keys, backups • Introduction of malware • Hardware failure • Software bugs • Network attacks CIT 380: Securing Computer Systems

  18. Calculate Risk • Cost-Benefit Analysis • Cost of Loss • Probability of Loss • Cost of Prevention • Levels of importance • High, Medium, Low • Best Practices CIT 380: Securing Computer Systems

  19. Cost-Benefit Analysis Cost of a Loss • Direct cost of lost hardware. • Cost of idle labor during outage. • Cost of time to recover. • Cost to reputation. Probability of a Loss • Insurance/power companies have some stats. • Records of past experience. Cost of Prevention • Remember that most risks cannot be eliminated. CIT 380: Securing Computer Systems

  20. Risk Analysis Notes Update your risks regularly • Business, technology changes alter risks. Too many risks to defend against. • Rank risks to decide which ones to mitigate. • Insure against some risks. • Accept other risks. CIT 380: Securing Computer Systems

  21. Best Practices • Risk Analysis is difficult and uncertain. • Follow best practices or due care • Firewall require as insurance co. due care. • Update patches, anti-virus. • Organizations differ in what they need. • Combine best practices + risk analysis. CIT 380: Securing Computer Systems

  22. Convincing Management • Security is not free. • MBA’s understand cost and benefits • MBA’s mistrust technology CIT 380: Securing Computer Systems

  23. Policy • Policy helps to define what you consider to be valuable, and it specifies which steps should be taken to safeguard those assets. CIT 380: Securing Computer Systems

  24. Three Policy Roles • What is being protected • Who is responsible • Provides ground on which to interpret and resolve later conflicts. CIT 380: Securing Computer Systems

  25. Role of Policy • Should be general and change little over time. • How does the NKU Acceptable Use Policy for Technology Resources meet these roles? CIT 380: Securing Computer Systems

  26. Security Policy Security policy partitions system states into: • Authorized (secure) • These are states the system is allowed to enter. • Unauthorized (nonsecure) • If the system enters any of these states, it’s a security violation. Secure system • Starts in authorized state. • Never enters unauthorized state. CIT 380: Securing Computer Systems

  27. Policy vs. Mechanism Security Policy • Statement that divides system into authorized and unauthorized states. Mechanism • Entity or procedure that enforces some part of a security policy. CIT 380: Securing Computer Systems

  28. Developing a Workable Policy • Assign an owner • Be positive • People respond better to do than don’t. • Remember that employees are people too • They will make mistakes • They value privacy • Concentrate on education • Standards for training and retraining CIT 380: Securing Computer Systems

  29. Standards • Codify successful security practices • Standards for backups (p. 46-7) • Platform independent • Metric to determine if met CIT 380: Securing Computer Systems

  30. Guidelines • Interpret standards for a particular environment. • Unix backups (p. 47) CIT 380: Securing Computer Systems

  31. Regulations • HIPAA • Medical Privacy - National Standards to Protect the Privacy of Personal Health Information • Sarbanes Oxley • Protecting of financial and accounting information • Federal Information Security Management Act (FISMA) • IT controls and auditing CIT 380: Securing Computer Systems

  32. Developing a Workable Policy • Have authority commensurate with responsibility • Spaf’s first principle of security administration: • If you have responsibility for security, but have no authority to set rules or punish violators, your own role in the organization is to take the blame when something big goes wrong. CIT 380: Securing Computer Systems

  33. Developing a Workable Policy • Be sure to know you security perimeter • Laptops and PDAs • Wireless networks • Computer used at home • Portable media • Flash drives, CDs, DVDs CIT 380: Securing Computer Systems

  34. Security Perimeter • Perimeter defines what is within your control. • Historically • Within walls of building or fences of campus. • Within router that connects to ISP. • Modern perimeters are more complex • Laptops, PDAs. • USB keys, CDs, DVDs, portable HDs. • Wireless networks. • Home PCs that connect to your network. CIT 380: Securing Computer Systems

  35. Defense in Depth • Firewall/IDS protect perimeter. • Perimeter security is not sufficient. • What if someone brings infected laptop to work? • What if home user bridges your net to Internet? • Defense in Depth • Multiple, independent layers of protection. • Network firewall + personal firewall + IDS CIT 380: Securing Computer Systems

  36. Four Easy Steps to a More Secure Computer • Decide how important security is for your site. • Involve and educate your user community. • Devise a plan for making and storing backups of your system data. • Stay inquisitive and suspicious. CIT 380: Securing Computer Systems

  37. Compliance Audit • Formulating policy is not enough by itself. It is important to determine regularly if the policy is being applied correctly, and if the policy is correct and sufficient. CIT 380: Securing Computer Systems

  38. Compliance Audits • Audit your systems and personnel regularly. • Audit failures may result from • Personnel shortcomings • Insufficient education or overwork • Material shortcomings • Insufficient resources or maintenance • Organizational shortcomings • Lack of authority, conflicting responsibilities • Policy shortcomings • Unforeseen risks, missing or conflicting policies CIT 380: Securing Computer Systems

  39. Providing Security • In-house staff • Full-time or part-time consultants • Choosing a vendor • “Reformed hacker” CIT 380: Securing Computer Systems

  40. Security Concepts • Security Through Obscurity • Responsible disclosure CIT 380: Securing Computer Systems

  41. Key Points • Policy divides system into • Authorized (secure) states. • Unauthorized (insecure) states. • Policy vs Mechanism • Policy: describes what security is. • Mechanism: how security policy is enforced. • Written policy and enforced policy will differ. • Compliance audits look for those differences. • Security Perimeter • Describes what is within your control. • Defense in depth: defend perimeter and inside. CIT 380: Securing Computer Systems

  42. References • Matt Bishop, Introduction to Computer Security, Addison-Wesley, 2005. • Simson Garfinkel, Gene Spafford, and Alan Schwartz, Practical UNIX and Internet Security, 3/e O’Reilly, 2003. • NKU, Acceptable Use Policy, http://it.nku.edu/itsecurity/docs/acceptableusepolicy.pdf, 2009. • SANS, SANS Security Policy Project, http://www.sans.org/resources/policies/ CIT 380: Securing Computer Systems