Applications & SystemsDevelopment

A very brief overview of the SDLC and the security issues involved.

Generic Systems Engineering Process

Discover Needs Define System Requirements Design System Architecture Develop Detailed Design Implement System Assess Effectiveness of System

SystemRequirements

SoftwareRequirements

Analysis

ProgramDesign

Coding

Testing

Operations &Maintenance

A simplistic software development model

SystemRequirements

SystemRequirements

Analysis

Design

Coding

Testing

Operations &Maintenance

The Waterfall development model

Going back only one stage limits rework and enhances control

SystemRequirements

SoftwareRequirements

ProductDesign

Coding

IntegrationProduct

Implementa-tion

Operations &Maintenance

A modified Waterfall development model that enforces comparison against specific baselines

Validation

Validation

Verification

Unit Testing

Verification

System Test

Revalidation

Verification: doing the job right

Validation: doing the right job

The Spiral Model

Cost Estimation Models :-)

• Basic COnstructive COst Model COCOMO – Cost as a function of lines of code

Man Months (MM) = 2.4 * 1000s of delivered source instructionsDevelopment Schedule = 2.5(MM).38

• Function Point Measurement Model– I/O types, internal file types, interfaces, etc

• Software Life Cycle Model (SLIM)– Manpower buildup index– Productivity factor

SystemRequirements

SoftwareRequirements

ProductDesign

Coding

IntegrationProduct

Implementa-tion

Operations &Maintenance

Security life cycle componentsValidation

Validation

Verification

Unit Testing

Verification

System Test

Revalidation

Info sec policy, standards, legal issues, early validation of concepts

SystemRequirements

SoftwareRequirements

ProductDesign

Coding

IntegrationProduct

Implementa-tion

Operations &Maintenance

Security life cycle componentsValidation

Validation

Verification

Unit Testing

Verification

System Test

Revalidation

Threats, vulnerabilities, sec requirements., reasonable care, due diligence, legal liabilities, cost/benefit, level of protection desired, test plans, validation

SystemRequirements

SoftwareRequirements

ProductDesign

Coding

IntegrationProduct

Implementa-tion

Operations &Maintenance

Security life cycle componentsValidation

Validation

Verification

Unit Testing

Verification

System Test

Revalidation

Incorporating security specs, adjust system & security test plans & data, determine access controls, design docs, evaluate encryption options, verification, business continuity plans

SystemRequirements

SoftwareRequirements

ProductDesign

Coding

IntegrationProduct

Implementa-tion

Operations &Maintenance

Security life cycle componentsValidation

Validation

Verification

Unit Testing

Verification

System Test

Revalidation

Develop security related code, unit testing, reuse other modules if possible, support business continuity plans, docs

SystemRequirements

SoftwareRequirements

ProductDesign

Coding

IntegrationProduct

Implementa-tion

Operations &Maintenance

Security life cycle componentsValidation

Validation

Verification

Unit Testing

Verification

System Test

Revalidation

Integrate security components, test integrated modules per plans, refine docs, conduct security related product verification

SystemRequirements

SoftwareRequirements

ProductDesign

Coding

IntegrationProduct

Implementa-tion

Operations &Maintenance

Security life cycle componentsValidation

Validation

Verification

Unit Testing

Verification

System Test

Revalidation

Install security software, run system conduct acceptance testing, test security software, certify docs & accreditation (if necessary)

SystemRequirements

SoftwareRequirements

ProductDesign

Coding

IntegrationProduct

Implementa-tion

Operations &Maintenance

Security life cycle componentsValidation

Validation

Verification

Unit Testing

Verification

System Test

Revalidation

Revalidate security controls, penetration testing, vulnerability analyses, manage change requests, implement change control, make changes, evaluate performance, update docs, recertify

Testing

• Unit testing

• Done by separate personnel

• Check all I/O, modules, files, security, etc

Extreme Programming (XP)Principles

• Feedback: most useful if it is done rapidly.

• Assuming simplicity: treating every problem as if it can be solved "extremely simply".

• Incremental changes: small releases

• Embracing change: not working against changes but embracing them.

Manifesto for Agile Software Development

• We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value: – Individuals and interactions over processes and tools– Working software over comprehensive documentation– Customer collaboration over contract negotiation– Responding to change over following a plan

• That is, while there is value in the items on the right, we value the items on the left more.

Maintenance Phase

1. Request Control• Establish request priorities, do• Cost estimates• User Interface• Determine tools to use, determine change effects

on other code2. Change Control

• Recreate & Analyze the problem• Develop changes & tests• Quality Control• Document changes, & recertify

3. Release Control

Software Capability Maturity Model (CMM)

• Phase 1: Initiate– Format improvement initiative– Management approval

• Phase 2: Diagnose– Assess current systems

• Phase 3: Establish Action Plan• Phase 4: Action• Phase 5: Leverage

– Review changes and process looking for improvements

Object Oriented Systems

• OO Requirements Analysis

• OO Aanalysis

• Domain Analysis

• OO Design

• OO Programming

• Object Request Brokers: CORBA, SOAP

Artificial Intelligence Systems

• Expert Systems (ES)– algorithm + data structures = Normal Program– Inference engine + knowledge base = ES

• Blackboards• Bayesian Networks• Fuzzy logic• Neural Networks: weighted inputs to “neurons”

yield outputs, “training period”• Genetic Algorithms: evolutionary computing,

fitness values, cross breeding, mutation

Database Systems

• Hierarchical• Mesh

• Object Oriented• Relational

DB Security Issues

• Views

• Granularity

• Aggregation: – combining higher sensitivity with lower

• Inference– Users “guessing” higher level values

• Multiple connections, backups, etc

• Data warehousing & Mining

Application Controls

• Service Level Agreements– Turn around time, avg response time, number

of users, system utilization rates, up times, transaction volumes, problem resolution

• Control Types– Preventative– Detective– Corrective

Preventative Controls

• Accuracy– Data checks, forms, custom screens, validity checks,

contingency planning, & backups

• Security– Firewalls, reference monitors, sensitivity labels, traffic

padding, encryption, data classification, one-time passwords, separation of development & testing

• Consistency– Data dictionary, programming standards & database

Detective Controls

• Accuracy– Cyclic redundancy checks, structured walk-

throughs, hash totals, reasonableness checks

• Security– Intrusion detection systems, audit trails

• Consistency– Comparison controls, relationship tests,

reconciliation controls

Corrective Controls

• Accuracy– Backups, control reports, before/after

imaging, checkpoint restarts

• Security– Emergency response & reference monitor

• Consistency– Program comments & database controls

System Architecture Issues

• Distributed Systems– Agents, applets, “sandbox,” virtual machines– P2P

• Centralized– Easier to protect

• Real Time