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Chapter 15
Essentials of Management Information Systems, 6e
Chapter 15 Information System Security and Control
Information System Security
and Control
© 2005 by Prentice Hall
Management Challenges
1. Achieving a sensible balance between too little
control and too much.
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2. Applying quality assurance standards in large
systems projects.
System Vulnerability and Abuse
Why Systems Are Vulnerable
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Accessibility to electronic data
Increasingly complex software, hardware
Network access points
Wireless vulnerability
Internet
System Vulnerability and Abuse
Threats to Computerized Information Systems
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Hardware failure
Software failure
Personnel actions
Terminal access
penetration
• Theft of data, services,
equipment
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Fire
Electrical problems
User errors
Unauthorized program
changes
• Telecommunication
problems
System Vulnerability and Abuse
Telecommunications networks vulnerabilities
Figure 15-1
System Vulnerability and Abuse
Window on Organizations
Credit Card Fraud: Still on the Rise
• To what extent are Internet credit card thefts
management and organizational problems, and to
what extent are they technical problems?
• Address the technology and management issues
for both the credit card issuers and the retail
companies.
• Suggest possible ways to address the problem.
System Vulnerability and Abuse
Why Systems Are Vulnerable
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Hacker
Trojan horse
Denial of service (DoS) attacks
Computer viruses
Worms
Antivirus software
System Vulnerability and Abuse
Window on Technology
Smarter Worms and Viruses:
The Worst Is Yet to Come
• Why are worms so harmful?
• Describe their business and organizational impact.
System Vulnerability and Abuse
Concerns for System Builders and Users
• Disaster
• Security
• Administrative error
• Cyberterrorism and Cyberwarfare
System Vulnerability and Abuse
Points in the processing cycle where errors can occur
Figure 15-2
System Vulnerability and Abuse
System Quality Problems: Software and Data
Bugs and Defects
Complete testing not possible
The Maintenance Nightmare
Maintenance costs high due to organizational
change, software complexity, and faulty system
analysis and design
System Vulnerability and Abuse
The cost of errors over the systems development cycle
Figure 15-3
System Vulnerability and Abuse
System Quality Problems: Software and Data
Data Quality Problems
Caused by errors during data input or faulty
information system and database design
Creating a Control Environment
Controls
• Methods, policies, and procedures
• Protection of organization’s assets
• Accuracy and reliability of records
• Operational adherence to management standards
Creating a Control Environment
General Controls and Application Controls
General Controls
• Govern design, security, use of computer
programs throughout organization
• Apply to all computerized applications
• Combination of hardware, software, manual
procedures to create overall control environment
Creating a Control Environment
General Controls and Application Controls
General Controls
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Software controls
Hardware controls
Computer operations controls
Data security controls
Implementation
Administrative controls
Creating a Control Environment
Security profiles for a personnel system
Figure 15-4
Creating a Control Environment
General Controls and Application Controls
Application Controls
• Automated and manual procedures that ensure
only authorized data are processed by application
• Unique to each computerized application
• Classified as (1) input controls, (2) processing
controls, and (3) output controls.
Creating a Control Environment
General Controls and Application Controls
Application Controls
Control totals:
Edit checks:
Computer matching:
Run control totals:
Report distribution logs:
Input, processing
Input
Input, processing
Processing, output
Output
Creating a Control Environment
Protecting the Digital Firm
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High-availability computing
Fault-tolerant computer systems
Disaster recovery planning
Business continuity planning
Load balancing; mirroring; clustering
Recovery-oriented computing
Managed security service providers (MSSPs)
Creating a Control Environment
Protecting the Digital Firm
Internet Security Challenges
• Public, accessible network
• Abuses have widespread effect
• Fixed Internet addresses
• Corporate systems extended outside organization
Creating a Control Environment
Internet security challenges
Figure 15-5
Creating a Control Environment
Protecting the Digital Firm
• Firewall screening technologies
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Static packet filtering
Stateful inspection
Network address translation
Application proxy filtering
• Intrusion detection systems
• Scanning software
• Monitoring software
Creating a Control Environment
Protecting the Digital Firm
Security and Electronic Commerce
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Encryption
Authentication
Message integrity
Digital signatures
Digital certificates
Public key infrastructure (PKI)
Creating a Control Environment
Public key encryption
Figure 15-6
Creating a Control Environment
Digital certificates
Figure 15-7
Creating a Control Environment
Protecting the Digital Firm
Security for Wireless Internet Access
• Service set identifiers (SSID)
– Identify access points in network
– Form of password for user’s radio network interface
card
– Broadcast multiple time per second
– Easily picked up by sniffer programs, war driving
Creating a Control Environment
Wi-Fi security challenges
Figure 15-8
Creating a Control Environment
Protecting the Digital Firm
• Wired Equivalent Privacy (WEP):
– Initial security standard
– Call for access point and all users to share the same 40bit encrypted password
• Wi-Fi Protected Access (WPA) specification
– 128-bit, non-static encryption key
– Data-packet checking
Creating a Control Environment
Developing a Control Structure: Costs and Benefits
Criteria for Determining Control Structure
• Importance of data
• Cost effectiveness of control technique
– Efficiency
– Complexity
– Expense
• Risk assessment: Level of risk if not properly
controlled
– Potential frequency of problem
– Potential damage
Creating a Control Environment
The Role of Auditing in the Control Process
MIS Audit
• Identifies all controls that govern individual
information systems and assesses their
effectiveness
• Lists and ranks all control weaknesses and
estimates the probability of their occurrence
Creating a Control Environment
Sample auditor’s list of control weaknesses
Figure 15-9
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
Development Methodology
• Collection of methods
• One or more method for every activity in every
phase of development project
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
Structured Methodologies
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Used to document, analyze, design information systems
Top-down
Process-oriented
Linear
Includes:
– Structured analysis
– Structured design
– Structured programming
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
Structured Analysis
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Defines system inputs, processes, outputs
Logical graphic model of information flow
Data flow diagram
Data dictionary
Process specifications
Ensuring System Quality: Software and Data
Data flow diagram for mail-in university registration system
Figure 15-10
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
Structured Design
• Set of design rules and techniques
• Promotes program clarity and simplicity
• Design from top-down; main functions and
subfunctions
• Structure chart
Ensuring System Quality: Software and Data
High-level structure chart for a payroll system
Figure 15-11
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
Structured Programming
• Organizes and codes programs to simplify control
paths for easy use and modification
• Independent modules with one entry and exit point
• Three basic control constructs:
– Simple sequence
– Selection
– Iteration
Ensuring System Quality: Software and Data
Basic program control constructs
Figure 15-12
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
Limitations of Traditional Methods
• Can be inflexible and time-consuming
• Programming depends on completion of analysis
and design phases
• Specification changes require changes in analysis
and design documents first
• Function-oriented
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
Unified Modeling Language (UML)
• Industry standard for analysis and design of
object-oriented systems
• Represents different views using graphical
diagrams
• Underlying model integrates views for consistency
during analysis, design, and implementation
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
UML Components
• Things:
– Structural things
– Behavioral things
– Grouping things
– Annotational things
Classes, interfaces,
collaborations, use cases, active
classes, components, nodes
Interactions, state machines
Packages
Notes
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
UML Components
• Relationships
– Structural
– Behavioral
Dependencies, aggregations,
associations, generalizations
Communicates, includes, extends,
generalizes
• Diagrams
– Structural
– Behavioral
Class, object, component, and deployment
diagrams
Use case, sequence, collaboration, stateschart,
and activity diagrams
Ensuring System Quality: Software and Data
A UML use-case diagram
Figure 15-13
Ensuring System Quality: Software and Data
A UML sequence diagram
Figure 15-14
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
Computer-Aided Software Engineering (CASE)
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Automation of step-by-step methodologies
Reduce repetitive development work
Support documentation creation and revisions
Organize design components; design repository
Support code generation
Require organizational discipline
Ensuring System Quality: Software and Data
Software Quality Assurance Methodologies and Tools
• Resource Allocation: Assigning costs, time,
personnel to different development phases
• Software Metrics: Quantified measurements of
systems performance
• Testing: Walkthroughs, debugging
Ensuring System Quality: Software and Data
Data Quality Audits and Data Cleansing
• Data Quality Audit
– Survey end users for perceptions of data quality
– Survey entire data files
– Survey samples from data files
• Data Cleansing
– Correcting errors and inconsistencies in data between
business units
Chapter 15 Case Study
Could a Missing Hard Drive Create Canada’s Biggest Identity Theft?
1. Summarize the ISM security problem and its
impact on ISM and its clients.
2. Describe the control weaknesses of ISM and
those of its clients that made it possible for this
problem to occur. What management,
organization, and technology factors contributed
to those weaknesses?
Chapter 15 Case Study
Could a Missing Hard Drive Create Canada’s Biggest Identity Theft?
3. Was the disappearance of the hard drive a
management problem, an organization problem,
or a technical problem? Explain your answer.
4. If you were responsible for designing security at
ISM and its client companies, what would you
have done differently? How would you have
solved their control problems?