Transcript IT255 Introduction to Information Systems Security Unit 8 Networks

IT255 Introduction to
Information Systems Security
Unit 8
Networks and Communications and
their Inherent Weaknesses
© ITT Educational Services, Inc. All rights reserved.
Learning Objective
Explain the importance of network principles
and architecture to security operations.
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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Key Concepts
 Open Systems Interconnection (OSI)
network model and its security lapses
 Physical and logical network topologies
 Characteristics of a secure network
 802.11 WLAN technology weaknesses,
vulnerabilities, and mitigation strategies
 Internet Protocol version 4 (IPv4) and
Internet Protocol version 6 (IPv6) and their
use in IT infrastructures for secure
communications
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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EXPLORE: CONCEPTS
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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OSI Network Model
 The seven-layer OSI reference
model organizes protocols and services
in levels of ordered operations.
 The protocol stack or network stack
refers to layered network protocols in the
OSI model.
 Lower-level protocols encapsulate
higher-level protocols as they descend
the protocol stack.
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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TCP/IP Explained
 Internet Protocol (IP) packets contain source
addresses and destination addresses to transmit
data.
 IP resides at the lower levels and encapsulates
upper-layer packets to send them across the
network.
 Transmission Control Protocol (TCP) builds
reliable connection-oriented transmissions.
 IP encapsulates TCP to connect sources with
destinations using certain ports and a specific
service protocol.
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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TCP/IP is Insecure
 It was designed in early 1980s as an open
standard.
 It was created before security was an issue.
Common issues with TCP/IP:
 TCP SYN attack
 IP spoofing
 Sequence guessing
 Source routing
 Connection hijacking
IT255 Introduction to Information Systems Security
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Insecure vs. Secure Application
Layer Protocols
Insecure Protocol
Secure Protocol
File Transfer Protocol (FTP) Secure File Transfer
Protocol (SFTP)
Hypertext Transfer Protocol Secure Hypertext Transfer
(HTTP)
Protocol (HTTPS)
Telnet
Simple Network
Management Protocol
(SNMP) v1/2
IT255 Introduction to Information Systems Security
Secure Shell (SSH)
SNMPv3
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Encapsulation
IT255 Introduction to Information Systems Security
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Topologies
 Network topology: The arrangement or
hierarchy of networked devices
IT255 Introduction to Information Systems Security
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Network Topology
Considerations
 It can help enforce security policies.
 Isolated segments for development and
production servers and user groups
compartmentalize risk.
 Security protocols help protect
confidentiality and integrity.
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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WLANs
 Institute of Electrical and Electronics
Engineers (IEEE) 802.11 a/b/g/n
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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EXPLORE: PROCESSES
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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Network Security Components
 Routers
 Switches
 Dual-homed
hosts
 Tunneling
IT255 Introduction to Information Systems Security
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Securing Network Environments
 Harden network
 Use non-routable addresses
 Isolate users in defined
domains and/or separate
groups
IT255 Introduction to Information Systems Security
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Remote Access and Wireless
User Considerations
 Isolate wireless users from wired
users.
 Separate remote user groups from
local user groups.
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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Summary
 The seven-layer OSI reference
model organizes protocols and services
in levels of ordered operations.
 TCP/IP is inherently insecure–use alternate
secure protocols.
 A topology is a representation of how
devices and systems interconnect.
 Network security components include
routers, switches, dual-homed hosts, and
tunneling.
IT255 Introduction to Information Systems Security
© ITT Educational Services, Inc. All rights reserved.
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