1. Introduction to Computer Security

2. Books: 1.An Inroduction to Computer Security: The NIST Handbook 2.Johannes Buchmann: Introduction to Cryptography 3.Douglas Stinson: Cryptography Theory and Practice

3. I. Outline of the semester Term of computer security Elements of computer security Three major security controls: Management controls, Operational controls, Technical controls Cryptography – encryption (symmetric, asymmetric), hash functions, digital signatures, message authentication codes, identification, key exchange etc.

4. II. Computer Security The protection afforded to an automated information system in order to attain the applicable objectives of preserving the integrity, availability and confidentiality of information system resources (includes hardware, software, information/data)

5. II. Computer Security Integrity: data integrity: Requirement that information and programs are changed only in a specified and authorized manner system integrity: Requirement that a system performs its intended function free from unauthorized manipulation

6. II. Computer Security Availability: Requirement intended to assure that systems work promptly and service is not denied to authorized users. Confidentiality: Requirement that private or confidential information not be disclosed to unauthorized individuals.

7. II. Elements of Computer Security 1.Computer security supports the mission of the organization 2.Computer security is an integral element of sound management 3.Computer security should be cost-effective 4.Computer security responsibilities should be made explicit 5.System owners have computer security responsibilities outside their own organizations 6.Computer security requires a comprehensive and integrated approach 7.Computer security should be periodically reassessed 8.Computer security is constrained by societal factors

8. II. Computer security supports the mission of the organization Computer security helps the organization’s mission by protecting its physical and financial resources, reputation, legal position, employees, and other tangible and intangible assets. No complete security  protecting important assets usually security is secondary (making profit, providing good service etc. is primary) Management should understand their mission and how their information system supports it.  security requirements are defined Interorganizational systems e.g.: good security of buyers system also benefits the seller

9. II. Computer security is an integral element of sound management Information and computer systems are often critical assets that support the mission of an organization. Protecting them can be as critical as protecting other organizational resources (e.g. money, physical assets, employees) Managers should decide about the level of risk they are willing to accept.

10. II. Computer security should be cost- effective Ensure that the cost of controls does not exceed expected benefits. Direct costs: purchasing, installing and administering security systems Indirect costs: Security systems can sometimes affect system performance, employee morale or retraining requirements.

11. II. Computer security responsibilities should be made explicit Document that states organization policy and make explicit computer security responsibilities Responsibilities may be internal to an organization or may extend across organizational boundaries.

12. II. Computer security requires a comprehensive and integrated approach Interdependencies of security controls – Managerial, operational and technical controls work together  interdependancies e.g.: training on how to use a secure system Other interdependencies – system management, legal issues, quality assurance

13. II. Computer security should be periodically reassessed Computers and the environments they operate in are dynamic  security requirements are ever-changing Changes in the system or the environment can create new vulnerabilities  necessary to reassess periodically

14. II. Computer security is constrained by societal factors Security may be limited by social issues e.g. security vs. privacy (identification, tracking actions)

15. III. Roles and Responsibilities Whose responsibility is it? Senior management Computer Security Management Program and Functional Managers/Application owners Technology providers Supporting organizations Users

16. III. Senior management Senior management – ultimate responsibility They establish the organization’s computer security program to support the mission of the organization. They are responsible for setting a good example for their employees

17. III. Computer Security Management Directs the organization’s day-to-day management of its computer security program Responsible for coordinating all security- related interactions among organizational elements.

18. III. Program and Functional Managers/Application owners Responsible for a program or function including the supporting computer system. These officials are usually assisted by technical staff.

19. III. Technology providers Managers and technicians who design and operate computer systems. They are responsible for implementing technical security on computer systems. Responsible for being familiar with security technology that relates to their system. Responsible for analyzing technical vulnerabilities. Telecommunications – providing communication services (fax, voice, etc.) Help desk – recognize security incidents and refer the caller to the appropriate person or organization for a response

20. III. Supporting organizations Audit – Auditors are responsible for examining systems whether the system is meeting stated security requirements. Quality assurance – Responsible for improving the products and services, how computer security can be used to improve the quality. Training office – Responsible for training users, operators, managers in computer security. Risk Management – Responsible for studying all types of risks including computer security- related risks.

21. III. Users Users of information Individuals who use information provided by the computer system. They may read computer- prepared reports etc. Users of systems Individuals who directly use computer systems, responsible for following security procedures, reporting security problems, attending security training.

22. IV. Threats Threats range from errors harming database integrity to fires destroying entire computer centers Threats from the actions of trusted employees, outside hackers, careless data entry clerks etc. Attack confidentiality, integrity of data or availability of a system

23. IV. Threats Knowledge of threat environment is necessary for system manager to implement the most cost-effective security measures. It might be more cost-effective to simply tolerate the expected losses  risk analysis

24. IV. Errors and omissions Threat to data and system integrity Made by users who create and edit data  training can help Large percentage of threats Contribute directly or indirectly to security problems

25. IV. Errors and omissions Directly: data entry error or programming error that crashes a system Indirectly: errors create vulnerabilities Errors in programming are called bugs Installation and maintenance errors  security vulnerabilities

26. IV. Fraud and theft Automating traditional methods of fraud and theft E.g.: financial systems are at risk, systems that control access to any resource (inventory systems etc.) Insiders (former employees also) are in a better position, outsiders Hardware and software are vulnerable to theft

27. IV. Employee sabotage Employees know what actions might cause the most damage Employee sabotage is believed to be much smaller than the instances of theft, but the cost of such incidents can be quite high.

28. IV. Loss of physical and Infrastructure support Includes power failures, loss of communication, water leaks, lack of transportation service, fire, flood etc. Loss of infrastructure often results in unexpected ways

29. IV. Malicious hackers/crackers A hacker breaks into computers and computer networks, either for profit or motivated by the challenge. Black hat (crackers) hackers: for malicious reasons such as vandalism, credit card fraud, identity theft, piracy, or other types of illegal activity White hat hackers: for non-malicious reasons, for instance testing their own security system Grey hat hackers: combination of a Black Hat and a White Hat Hacker (repair the system for a small fee)

30. IV. Malicious hackers/crackers Losses due to hacker attacks are significantly smaller than losses due to insider theft and sabotage, the hacker problem is widespread and serious. Receive more attention: hacker threat is a more recently encountered threat, organizations do not know the purpose of a hacker (browse, steal, damage, etc.)  no limitations, hackers’ identity is unknown (case of painter and burglar)

31. IV. Industrial espionage Gathering proprietary data from private companies or the government for the purpose of aiding another company. Goal is to improve their competitive advantage. Since information is processed and stored on computer systems, computer security can help. (employees may sell information) E.g.: pricing information, product development, customer lists, sales data, cost data, strategic plans

32. IV. Malicious code Virus: A code segment that replicates by attaching copies of itself to existing executables. The new copy of the virus is executed when a user executes the new host program. Trojan horse: A program that performs a desired task, but that also includes unexpected functions. They steals information, harm the system and do not replicate themselves.

33. IV. Malicious code Worm: A self-replicating program that is self- contained and does not require a host program. The program creates a copy of itself and causes it to execute, no user intervention is required. Sometimes just consume bandwith.

34. IV. Threats to personal privacy Electronic information about individuals by governments, credit bureaus, private companies, etc. have created a threat to individual privacy. Often referred to „Big Brother”. Federal and state employees have sold personal information collected by the government. (1992, USA)

35. V. Major Controls Management Controls: Focus on controls that can be characterized as managerial. e.g.: management of computer security program, management of risk within the organization, management of assurance etc. Operational Controls: Focus on controls that are implemented and executed by people e.g.: training, education, user administration, software support, documentation etc. Often require technical or specialized expertise and rely upon management activities as well as technical controls

36. V. Major Controls Technical Controls: Focus on security controls that the computer system executes. e.g.: identification, access control, other cryptographic technologies

37. V. Management controls – Computer security policy Policy is senior management’s directives to create a computer security program, establish its goals, and assign responsibilities. Computer security policy is defined as the documentation of computer security decisions. Computer security policy protects both technical and information resources as well as guiding employee behavior.

38. V. Management controls – Computer security policy Program policy is used to create an organization’s computer security program. Issue-specific policies address specific issues of concern to organization. System-specific policies focus on decisions taken by mangement to protect a particular system.

39. V. Management controls – Computer security policy Management issues program policy to establish the organization’s computer security program and its basic structure. Components of the policy: purpose, scope responsibilities, compliance Purpose: why the program is being established, the goals of the program e.g.: integrity, availability, confidentiality, reduction in errors and data loss, maintaining confidential personal data

40. V. Management controls – Computer security policy Scope: which resources the computer security program covers including facilities, hardware, software, information and personnel. Responsibilities: management of a computer security program is assigned to an office. Responsibilities of officials and offices need to be addressed, including managers, applications owners, users etc.

41. V. Management controls – Computer security policy Compliance: General compliance to ensure meeting the requirements to establish a program is needed. An office is assigned to responsibility for monitoring compliance. The use of specified penalties and disciplinary actions is necessary.

42. V. Management controls – Issue- specific policy Focuses on areas Program policy does not require much modification over time, whereas issue-specific policies require more frequent revision. e.g.: particular methodology for managing risk, new issues arise, internet access (which type of systems may be connected to the network, user authentication for Internet- connected systems)

43. V. Management controls – Issue- specific policy Components: Managers must define the issue with conditions Clearly state the organization’s position Clarify where, how, when, to whom and to what a particular policy applies. Need to be clarified who is responsible for the issue

44. V. Management controls – Issue- specific policy Components: Penalties may be explicitly stated and should be consistent with organizational personnel policies and practices. Appropriate positions (individuals) are needed to contact for further information.

45. V. Management controls – System- specific policy System-specific policy is much more focused, than program and issue-specific policy. It addresses only one system. Often accompanied by implementing procedures and guidelines Two-level model: security objectives and operational security rules

46. V. Management controls – System- specific policy Security objectives should be defined concretly e.g.: Only individuals in the accounting and personnel departments are authorized to provide or modify information used in payroll processing. Rules for operating a system are given, who can do what e.g.: Personnel clerks may update fields for weekly attendance, charges to annual leave, employee addresses, and phone numbers.

47. V. Management controls – Risk management Risk is the possibility of something adverse happening. Risk management is the process of assessing risk, taking steps to reduce risk to an acceptable level and maintaining that level of risk. Computer security risk management addresses risks which arise from an organization’s use of information technology.

48. V. Management controls – Risk management E.g.: To maximize the return on their investments, businesses must often decide between aggressive (but high-risk) and slow-growth (but more secure) investment plans. These decisions require analysis of risk.  Management decides There is always risk. (from trusted employees or fire etc.) Risk management is made up of three activities: risk assessment, risk mitigation and uncertainty analysis

49. V. Management controls – Risk management – Risk assessment Risk assessment: Process of analyzing and interpreting risk Basic activities: determining the assessment’s scope and methodology Collecting and analyzing data Interpreting the risk analysis results

50. V. Management controls – Risk management – Risk assessment Determining the assessment’s scope and methodology: Identify the system or part of the system that will be analyzed Chose the analytical method including its level of detail and formality Different parts of a system may be analyzed in greater or lesser detail The more essential the system, the more thorough the risk analysis should be Defining the scope and boundary can help ensure a cost effective assessment.

51. V. Management controls – Risk management – Risk assessment Collecting and analyzing data: Risk has many different components: assets, threats, vulnerabilities, safeguards, consequence, likelihood Gathering data about the threatened area and synthesizing and analyzing the information. Screening: the process to limit information gathering and analysis, since we might collect much more information than can be analyzed.

52. V. Management controls – Risk management – Risk assessment Collecting and analyzing data: Asset valuation: Asset includes the information, software, personnel, hardware and physical assets. The value of an asset consists of its intrinsic value and near-term impacts and long- term consequences of its compromise. Consequence assessment: estimates the degree of harm or loss that could occur. E.g.: disclosure, modification, denial of service, loss of reputation, loss of business, etc.

53. V. Management controls – Risk management – Risk assessment Collecting and analyzing data: Threat identification: Threat is an entity or event with the potential to harm the system. Threats should be identified and analyzed to determine the likelihood of their occurrence and their potential to harm assets. Safeguard analysis: A safeguard is any action, device, procedure, technique, or other measure that reduces a system’s vulnerability to a threat. Safeguard analysis should include an examination of the effectiveness of the existing security measures.

54. V. Management controls – Risk management – Risk assessment Collecting and analyzing data: Vulnerability analysis: A vulnerability is a condition or weakness in security procedures, technical controls, or other controls that can be exploited by a threat. Vulnerabilities are often analyzed in terms of missing safeguards. Likelihood assessment: Likelihood is an estimation of the frequency or chance of a threat happening. A likelihood assessment considers the presence, strengths of threats as well as the effectiveness of safeguards.

55. V. Management controls – Risk management – Risk assessment Interpreting risk analysis results: Risk analysis results are typically represented quantitatively and/or qualitatively. Quantitative measures: e.g. reduced expected monetary losses Qualitative measures: descriptive e.g. high, low, or a scale of 1 to 10

56. V. Management controls – Risk management – Risk mitigation Selecting safeguards Method of selecting safeguards: what if analysis to test what difference each makes with regard to cost, effectiveness and other factors E.g.: what if passwords are strengthened? Personnel may be required to change passwords more frequently. There are no direct monetary expenditure, but staff and administrative overhead is increased.

57. V. Management controls – Risk management – Uncertainty analysis Risk management often must rely on speculation, best guesses, incomplete data, and many unproven assumptions. Sources of uncertainty: lack of confidence or precision in the risk management model or lack of sufficient information to determine the exact value of the elements of the risk model

58. VI. Operational Control - Personnel issues Staffing process: Position definition - in the process of defining a position, security issues should be identified – Separation of duties (one initiates a request for a payment, another authorizes that same payment) – Least privilege (access management) Determining position sensitivity - level of sensitivity is based upon such factors as the type and degree of harm (e.g., disclosure of private information, interruption of critical processing, computer fraud) Filling the position – which applicants meet the position requirements (screening process) Training and awareness - employees still have to be trained to do their job, which includes computer security responsibilities and duties

59. VI. Operational Control – Awareness, Training and Education improving awareness of the need to protect system resources developing skills and knowledge so computer users can perform their jobs more securely building in-depth knowledge, as needed, to design, implement, or operate security programs for organizations and systems

60. VI. Operational Control – Awareness, Training and Education AWARENESSTRAININGEDUCATION Attribute:"What""How""Why" Level:InformationKnowledgeInsight Objective:RecognitionSkillUnderstanding Teaching Method:Media (Videos, Posters, Newsletters…) Practical Instruction (Lecture, Case study workshop…) Theoretical Instruction (Seminar, reading…) Test Measure:True/False, Multiple Choice Problem Solving (apply learning) Essay (interpret learning) Impact Timeframe:Short-termIntermediateLong-term

61. VI. Operational Control – Computer Support and Operations This includes both system administration and tasks external to the system that support its operation (e.g., maintaining documentation). It does not include system planning or design. Support and operations are routine activities that enable computer systems to function correctly. (e.g. fixing software or hardware problems, maintaining software)

62. VI. Operational Control – Computer Support and Operations User Support: – through a Help Desk – which problems are security-related – they may not be aware of the "whole picture„ Software Support: – controlling what software is used on a system ( must not load any) – ensure the software has not been modified without proper authorization (This can be done with a combination of logical and physical access controls.)

63. VI. Operational Control – Computer Support and Operations Configuration Management: – process of keeping track of changes to the system and, if needed, approving them – the security goal is to know what changes occur, not to prevent security from being changed Backups: – Support and operations personnel and sometimes users back up software and data – Frequency of backups will depend upon how often data changes and how important those changes are. – Finally, backups should be stored securely

64. VI. Operational Control – Computer Support and Operations Media Controls: – include a variety of measures to provide physical and environmental protection and accountability for CDs, printouts and other media – prevent the loss of confidentiality, integrity, or availability of information, including data or software, when stored outside the system – Physical and environmental protection is used Marking: – Controlling media may require some form of physical labeling – e.g.: special handling instructions, to locate needed information

65. VI. Operational Control – Computer Support and Operations Logging: – to support accountability – Control numbers (or other tracking data), the times and dates of transfers, names and signatures of individuals involved, and other relevant information Integrity Verification: – no modification – error detection and correction, cryptographic- based technologies

66. VI. Operational Control – Computer Support and Operations Physical Access Protection: – Media can be stolen, destroyed, replaced with a look-alike copy, or lost. – Physical access controls, which can limit these problems, include locked doors, desks, file cabinets, or safes. Environmental Protection: – media should be protected against heat, liquids, dust etc. Disposition – The process of removing information from media is called sanitization. – e.g.: overwriting, destruction by shredding or burning

67. VI. Operational Control – Computer Support and Operations Documentation : – Ensure continuity and consistency – new personnel sufficiently detailed instructions – E.g. : security plans, contingency plans, risk analyses, and security policies and procedures Maintenance: – System maintenance requires either physical or logical access to the system – Support and operations staff, hardware or software vendors, or third-party service providers may maintain a system

68. VI. Operational Control – Physical and environmental security refers to measures taken to protect systems, buildings, and related supporting infrastructure against threats associated with their physical environment three areas: – the building, other structure, or vehicle housing the system and network components; determine the level of such physical threats as fire, roof leaks, or unauthorized access – facility's general geographic operating location determines the characteristics of natural threats, which include earthquakes and flooding; man-made threats such as burglary or damaging nearby activities, including toxic chemical spills, explosions, fires, and electromagnetic interference – system's operation usually depends on supporting facilities such as electric power, heating and air conditioning, and telecommunications.

69. VI. Operational Control – Physical and environmental security Interception of Data – Direct Observation - terminal and workstation display screens – Interception of Data Transmissions - access to data transmission lines – Electromagnetic Interception - Systems routinely radiate electromagnetic energy that can be detected with special-purpose radio receivers. (TEMPEST attack)

70. Technical Control – Identification, Entity authentication Identification is the means by which a user provides a claimed identity to the system. Entity authentication is the means of establishing the validity of this claim. – something the individual knows (e.g.: password, PIN) – something the individual possesses (e.g.: smart card, token) – something the individual is (e.g.: biometric)