1. IS Network and Telecommunications Risks
Chapter Six
IS Network
and
Telecommunications Risks

2. Topics Network and Telecommunication Technologies
Risks to IT Network and Telecommunication Systems
IT Network and Telecommunication Security
Auditing Network Security

3. Network Types By Scale By Ownership Local Area Network (LAN)
Backbone Networks (BN)
for linking together organizational LANs at various locations.
Metropolitan Area Network (MAN)
connects LANs and BNs across different locations (usually leased lines)
Wide Area Network (WAN)
By Ownership
Internet, intranet, extranet
Virtual private networks (VPN)

4. Network Types By Topology By Distribution of Functionality
Star-shaped – centralized
Ring – decentralized
Bus – decentralized
Mesh
By Distribution of Functionality
Client Server, Thin Client, Fat Client

5. Network Components Computers and terminals Network Operating System
(Users and Applications)
Computers and terminals
Network Operating System
Telecommunications processors (network interface cards and modems)
Telecommunications channels – physical and wireless (media)
Devices (Routers, switching, hubs, etc.)
Clients/Servers
Network Infrastructure

6. Network Protocols and Software
Network and telecommunications software
application software (web browsers, software, etc.),
network OS,
networks management software,
middleware

7. Multi-layer Network Models
Network models – standard architecture that allows different HW and SW to communicate across networks
Open Systems Interconnection Model (7 layer)
Created by International Standards Organization (ISO) in 1984
Internet Model (5 layer)
Created by DARPA originally in early 70’s
Based on Transmission Control Protocol/ Internet Protocol (TCP/IP) suite
Combines the “top” three layers of the OSI model into a single layer.

8. 5-Layer Internet Model Application Layer Transport Layer Network Layer
Application Software
Application Layer
set of utilities used by application programs
Transport Layer
deals with end-to-end issues such as segmenting the message for network transport, and maintaining the logical connections between sender and receiver
Network Layer
responsible for making routing decisions
Data Link Layer
deals with message delineation, error control and network medium access control
Physical Layer
defines how individual bits are formatted to be transmitted through the network
System Software
Computer Hardware

9. Data Communication Standards
Layer
Common Standards
5. Application layer
HTTP, HTML (Web)
IMAP, POP ( )
4. Transport layer
TCP (Internet)
SPX (Novell LANs)
3. Network layer
IP (Internet)
IPX (Novell LANs)
2. Data link layer
Ethernet (LAN)
PPP (dial-up via modem for MAN)
1. Physical layer
Category 5 twisted pair (LAN)
Fiber optic cable (WAN)

10. Message Transmission Example

11. Message Moving Through Layers

12. IS Network and Telecommunications Risks
Social Engineering, Software Vulnerabilities (Unauthorized Access)
Physical Infrastructure Threats – the elements, natural disasters, power supply, intentional human attacks (disaster)
Programmed Threats – viruses, worms, Trojan horses, hoaxes, blended threats (destruction)
Denial of Service Attacks (disruption)

13. IS Network and Telecommunications Security
Network security administration
Authentication and Access Control
Encryption – secret key and public key
Firewalls – packet filtering and stateful inspection
Intrusion Detection Systems
Penetration Testing – war dialing, port scanning, sniffers, password crackers

14. Internal, Perimeter, and External Networks

15. Auditing Network Security
Risk assessment and best practices
Benchmark tools
IT audit programs for network security