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Information Systems Security

Information Systems Security. Applications Development Domain #8. Objectives. Software Flaws OSI Model Database Concepts Software Lifecycle Change Control OOP Expert Systems. Why Security is Lacking?. Software vendors rush to market Security professionals are not software developers

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Information Systems Security

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  1. Information Systems Security Applications Development Domain #8

  2. Objectives • Software Flaws • OSI Model • Database Concepts • Software Lifecycle • Change Control • OOP • Expert Systems

  3. Why Security is Lacking? • Software vendors rush to market • Security professionals are not software developers • Public is used to software with bugs • Software vendors not held liable • Programmers not taught secure coding in school • Note: Average 10 bugs every 1K lines

  4. Usual Steps • Buggy software released to market • Hackers find vulnerabilities • Web sites post vulnerabilities • Vendors develop patches • Sits on network administrators desks to be tested and installed

  5. Where to Implement • Security should be planned and managed throughout the lifecycle • Not to be added as an afterthought • Should not be forsaken due to deliverable deadlines • Focus on security AND functionality

  6. Functional Requirements • Specific system functionalities • Consider how the parts of the system should interoperate • Deliverable from this phase of development is a functional requirements document

  7. Design • Determine how exactly the various parts of the system will interoperate • How the modular system structure will be laid out • Lay out initial timelines for completion of coding milestones • Deliverable is formal design documents

  8. Code Review Walk-Through • Schedule several code walk through meetings • Involve only development personnel • Look for problems in logical flow or security

  9. System Testing • Perform the initial system tests using development personnel • Agree that the system meets all functional requirements • Deliverable is beta code

  10. Certification/Accreditation • Normally required by defense contractors • Certification is the comprehensive evaluation of the technical and non-technical security features of an IT system • Accreditation is the formal declaration by the approved authority that an IT system is approved to operate in a particular security mode

  11. Maintenance • Ensure continued operation in the face of changing operational, data processing, storage, and environmental requirements • Changes to the code be handled through a formalized change request/control process

  12. Life Cycle Models • Formalized life cycle management process • Royce and Boehm proposed several software life cycle models • In 1991, the Software Engineering Institute introduced the Capability Maturity Model

  13. Waterfall Model • Developed by Royce in 1970 • Series of iterative activities • 7 stages of development • System requirements • Software requirements • Preliminary design • Detailed design • Code/debug • Testing • Maintenance

  14. Waterfall Model • Allows development to return to previous phase to correct defaults discovered • 1st comprehensive model to allow a step back. • Only allows the developers to step back one phase in the process

  15. Spiral Model • Developed by Boehm in 1988 at TRW • Multiple iterations • Each loop of the spiral results in a system prototype • Allows developers to return to the planning stage based on changing technical demands and customer requirements

  16. Software Capability Maturity • Developed at CMU in 1991 • Repeatable – reuse of code begins • Defined – developers use formal processes • Managed – quantitative measures utilized • Optimized – process of continuous improvement

  17. Security Control Architecture • Process isolation • Fundamental security procedures put into place during system design • Hardware segmentation • Process isolation at the hardware level by enforcing memory access constraints

  18. Protection Rings • Layer 0 – where the OS kernel resides • Has full control of all system resources • Layer 1 & 2 – device drivers and OS interfaces • Most O/S do not implement these layers • Layer 3 – user applications and processes • Known as user mode • Not allowed direct access to system resources

  19. Ring 0 – Reference Monitor • Must be tamperproof • Must always be invoked • Small enough to be analyzed • Must be complete

  20. Virus • Piece of code that requires a host application to reproduce • Macro • Boot sector • Compression • Stealth • Polymorphic • Multi-partite • Self-garbling

  21. Virus • Fred Cohen wrote the 1st in 1983 • Called the morris worm • Over 60,000 viruses today • Main functions – propagation and destruction

  22. Types of Viruses • File Infectors • Boot Sector Infectors • Companion Virus • Email Virus • Multi-partite

  23. More Malware • Worms • Can reproduce on their own • Self contained • Logic bomb • Event triggers execution • Trojan horse • Disguised as another program • Uses program to exploit authorization process

  24. MORE • DDoS Zombies • Spyware/Adware • Pranks

  25. Threats in Software Environment • Buffer Overflow • Citizen Programmers • Covert Channels: Storage and Timing • Malware • Malformed Input • Object Reuse • Mobile Code • Time of Check/Time of Use

  26. System Development Life Cycle • Project Initiation • Functional Requirements • System Design • Develop • Acceptance • Installation • Maintenance • Revisions

  27. Software Protections Mechanisms • Security Kernel (Monitor) • Processor Privilege State • Buffer Overflow Controls • Incomplete Parameter Controls • Memory Protection • Covert Channel Controls • Cryptography

  28. Database Vulnerabilities • Aggregation • Bypass Attacks • Deadlocking • Query Attacks • Web Security • Compromising Database Views

  29. Database Protection • Lock Controls • View Based Controls • Grant/Revoke Controls • Metadata Controls • Data Contamination Controls

  30. Distributed Components • Agents • Performs actions on behalf of user • Carries out activities unattended • Applets • Sent from server to client • Self contained mini-programs • Java (Sun) & ActiveX (MS) • Java ‘sandboxed’ but Active X is ring 0

  31. Databases • Relational • Flat 2-dimensional table • # of rows is cardinality • # of columns is degree • Security available through views • Primary & secondary keys used • Data Warehouses & Data Mining

  32. Expert Systems • Accumulated knowledge of expert on a specific subject • Knowledge base • Inference engine • Fuzzy logic • Neural networks

  33. Programming • Interpreted versus compiled • Fail-secure versus fail-open • Reverse engineering • White box testing versus black box testing

  34. Password Attacks • Dictionary attacks • Against /etc/passwd in Unix • Compares hash values • Social engineering • Brute force attacks • Complex passwords

  35. DOS Attacks • SYN flood • DDOS • Tribal Flood Network (TFN) • DRDos attacks • Smurf (ICMP • Fraggle (UDP) • Teardrop (fragmentation) • Land (tight loop for old systems) • Ping of Death (larger than 64K packets)

  36. More Attacks • Buffer Overflows • Combat with input controls • Time of check/Time of use • Restrictions only checked at login • IP probes or sweeps (Ping) • Port scans to identify services • Vulnerability attacks (Satan) • IP spoofing

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