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Telecommunications and
Network Security
Muhammad Wajahat Rajab
Domain Overview
• Deals with digital communication mechanism by
concentrating on the security aspect!
Mind Exercises
• Divide 30 by half and add ten. What do you get?
• A farmer had 17 sheep. All but 9 died. How many
alive s...
Network Concepts
Data Network Types
• Local Area Network (LAN)
• Wide Area Network (WAN)
• What is intranet?
• What is extranet?
OSI Reference Model
• Adopted by ISO in 1984
• Defines standard protocols for communication and
interoperability by using ...
OSI Reference Model
• Advantages
– Clarifies the functions of a communication process
– Reduces complex networking process...
OSI Layers
• Application Layer
• Presentation Layer
• Session Layer
• Transport Layer
• Network Layer
• Data Link Layer
• ...
Application Layer
• Serves as the interface between user and the
communication technologies
– SMTP, FTP, HTTP
Presentation Layer
• Ensures communication between different data
representations
– ASCII, EBCDIC, JPEG, MPEG, GIF
Session Layer
• Establishes, maintains and terminates sessions
between applications
– SQL, RPC
Transport Layer
• Provides reliable, transparent transfer of data
between end points
– TCP, UDP
Network Layer
• Provides routing and forwarding functionalities
– IP, DHCP
Data Link Layer
• Provides reliable transfer of information across the
physical link
– Ethernet, Token Ring
Physical Layer
• Concerned with transmission of unstructured bit
streams over physical medium
– E1, T1
TCP/IP Model
Topologies
Wireless Networks
FHSS
• Frequency Hoping Spread Spectrum
– Takes the total bandwidth and splits it into smaller sub-
channels
DSSS
• Direct Sequence Spread Spectrum
– Applies sub-bits to a message
• The sub-bits are used to generate a different for...
OFDM
• Orthogonal Frequency Division Multiplexing
Data Link Layer
• WLAN technologies and protocols
Type Speed Frequency Modulation Description
802.11 1 Mbps 2.4 Ghz DSSS L...
Security Flaws
• No user authentication
• No mutual authentication
• Flawed encryption protocol
– Allows specific bits to ...
WEP
• Wired Equivalent Privacy
– Used to provide confidentiality
– Uses stream cipher RC4
– Versions
• WEP-64 and WEP-128
...
WEP
• Open System Authentication
– Any client, regardless of its WEP keys, can associate itself
with the Access Point
– No...
WEP
• Shared Key Authentication
– A four-way challenge-response handshake is used
• Client sends an authentication request...
WPA
• WiFi Protected Access
– Uses Temporal Key Integrity Protocol (TKIP)
• Adds 48 bit IV value
• Implements a frame coun...
WPA
• WPA Modes
– Enterprise Mode
• Requires an authentication server
• Uses RADIUS protocols for authentication and key d...
WPA2
• WiFi Protected Access 2
– Replaces TKIP with CCMP
• Counter Mode with Cipher Block Chaining Message Authentication
...
Network Attacks
DNS Poisoning
SYN Flood
ARP Poisoning
Request
140.252.13
.1 .2 .3 .4 .5
08:00:20:03:F6:42 00:00:C0:C2:9B:26
Reply
140.252.13
.1 .2 .3 .4 .5
08:00:...
Network Sniffing
… telnet Router5
User Access Verification
Username: squiggie
password: Sq%*jkl[;T
Router5>ena
Password: j...
IP Spoofing
A
B
C
Attacker
DDOS Attack
Attacker
Innocent handler
Victim
A
Innocent handler
Innocent agents
Innocent agents
Attack Alice
NOW !
Smurf Attack
172.15.0.0
Muddasar Yasir
1 ICMP Echo Req
Src: Yasir
Dest:
172.15.255.255
2 ICMP Echo Reply
Dest: Dos Target
Virtual Private Networks
Introduction
• A private network that uses a public network to
connect remote sites or users together!
Concept
Features of VPN
• Security
• Reliability
• Scalability
• Network management
• Policy management
VPN Concepts
• Encapsulation
– Inclusion of one data structure within another structure
• Encryption
– Hiding of real info...
Tunneling Protocols
• PPTP
• L2F
• L2TP
• IPSec
PPTP
• Point to Point Tunneling Protocol
– Designed for client/server connectivity
– Sets up a single point-to-point conne...
L2F
• Layer 2 Forwarding
– Created before L2TP by Cisco
– Merged with PPTP, which resulted in L2TP
– Provides mutual authe...
L2TP
• Layer 2 Tunneling Protocol
– Hybrid of L2F and PPTP
– Sets up a single point-to-point connection between two
comput...
IPSec
• Internet Protocol Security
– Handles multiple connections at the same time
– Provides secure authentication and en...
Benefits of VPN
• Extend geographic connectivity
• Improve security
• Improve productivity
• Simplify network topology
• P...
Intrusion Detection Systems
Introduction
• A system that detects and logs
– Inappropriate, Incorrect, or Anomalous activity
Types
• Network based IDS
• Host based IDS
Methods
• Pattern matching
– Signature based
• Anomaly detection
– Checks any abnormality
• Protocol behavior
– Checks cor...
Events
• True positive
– When the IDS sets off an alert and it is a real attack
• True negative
– When the IDS does not se...
Firewalls
Introduction
• A system that prevents unauthorized access
– To or from a network
• Controls the flow of traffic
Concept
Firewall Types
• Packet filtering firewall
• Proxy firewall
– Application level proxy
– Circuit level proxy
• Stateful ins...
Packet Filtering Firewall
• Governed by set of directives
• Works at network layer
• Makes decisions on
– Packet’s source ...
Packet Filtering Firewall
• Ingress Filtering
– Blocking inbound traffic
• Egress Filtering
– Blocking outbound traffic
Application Level Proxy
• Contains a proxy agent
• Does not allow a direct communication
• Operates at the application lev...
Circuit Level Proxy
• Creates a circuit between client and the server
• Works at session layer
• Knows the source and dest...
Stateful Inspection Firewall
• Tracks the state of connections
• Blocks packets deviating from expected state
• Works same...
Dynamic Packet Filtering
Kernel Proxy Firewalls
• Fifth generation firewall!
• Creates dynamic, customized TCP/IP stacks for packet
evaluation
• Wh...
Firewall Architectures
• Screening Router
• Dual Homed Gateways
• Screened Host Gateways
• Screened Subnet
Screening Router
Screening Router
• Screening Router
– A router placed between trusted and public networks
– Security policy implemented us...
Dual Homed Gateway
Dual Homed Gateways
• A single computer with separate NICs connected to
each network
• Used to divide internal trusted net...
Screened Host Gateways
Screened Host Gateways
• Employs external screening router and internal
bastion host
• Advantages:
– Provides distributed ...
Screened Subnet
Screened Subnet
• Deploys external screening router, internal bastion
host and internal screening router
• Concept of DMZ
...
Unified Threat Management
• Single system with all the solutions
• Contains firewall, malware detection and eradication,
s...
Why Firewall Security
• Remote login
• Application backdoors
• Operating system bugs
• Denial of service
• Spam
• Source r...
Best Practices
• Change the default configurations
• ACLs should be simple and direct
• Disallow source routing
• Close un...
Thank You! 
• Any Questions?
Questions
Question 1
• Which of the following is not a security goal
for remote access?
A. Reliable authentication of users and syst...
Question 1
• Which of the following is not a security goal
for remote access?
A. Reliable authentication of users and syst...
Question 2
• Which of the following is the biggest concern
with firewall security?
A. Internal hackers
B. Complex configur...
Question 2
• Which of the following is the biggest concern
with firewall security?
A. Internal hackers
B. Complex configur...
Question 3
• Which of the following should NOT normally
be allowed through a firewall?
A. SNMP
B. SMTP
C. HTTP
D. SSH
Question 3
• Which of the following should NOT normally
be allowed through a firewall?
A. SNMP
B. SMTP
C. HTTP
D. SSH
Question 4
• Which type of attack involves the alteration of
a packet at the IP level to convince a system
that it is comm...
Question 4
• Which type of attack involves the alteration of
a packet at the IP level to convince a system
that it is comm...
Question 5
• Which of the following statements pertaining
to packet filtering is incorrect?
A. It is based on ACLs
B. It i...
Question 5
• Which of the following statements pertaining
to packet filtering is incorrect?
A. It is based on ACLs
B. It i...
Question 6
• What is the main characteristic of a multi-
homed host?
A. It is placed between two routers or firewalls
B. I...
Question 6
• What is the main characteristic of a multi-
homed host?
A. It is placed between two routers or firewalls
B. I...
Question 7
• One drawback of Application Level Firewall is
that it reduces network performance due to
the fact that it mus...
Question 7
• One drawback of Application Level Firewall is
that it reduces network performance due to
the fact that it mus...
Question 8
• Address Resolution Protocol (ARP)
interrogates the network by sending out a?
A. Broadcast
B. Multicast
C. Uni...
Question 8
• Address Resolution Protocol (ARP)
interrogates the network by sending out a?
A. Broadcast
B. Multicast
C. Uni...
Question 9
• As a result of a risk assessment, your security manager
has determined that your organization needs to
implem...
Question 9
• As a result of a risk assessment, your security manager
has determined that your organization needs to
implem...
Question 10
• What refers to legitimate users accessing
networked services that would normally be
restricted to them?
A. S...
Question 10
• What refers to legitimate users accessing
networked services that would normally be
restricted to them?
A. S...
Thank You! 
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Telecommunications and Network Security Presentation

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Telecommunications and Network Security Presentation

  1. 1. Telecommunications and Network Security Muhammad Wajahat Rajab
  2. 2. Domain Overview • Deals with digital communication mechanism by concentrating on the security aspect!
  3. 3. Mind Exercises • Divide 30 by half and add ten. What do you get? • A farmer had 17 sheep. All but 9 died. How many alive sheep were left? • Some months have 30 days, some months have 31 days. How many months have 28 days?
  4. 4. Network Concepts
  5. 5. Data Network Types • Local Area Network (LAN) • Wide Area Network (WAN) • What is intranet? • What is extranet?
  6. 6. OSI Reference Model • Adopted by ISO in 1984 • Defines standard protocols for communication and interoperability by using a layered approach • Follows Divide and Conquer Rule?
  7. 7. OSI Reference Model • Advantages – Clarifies the functions of a communication process – Reduces complex networking processes – Promotes interoperability by defining standard interfaces – Aids development – Facilitates easier and more logical troubleshooting
  8. 8. OSI Layers • Application Layer • Presentation Layer • Session Layer • Transport Layer • Network Layer • Data Link Layer • Physical Layer
  9. 9. Application Layer • Serves as the interface between user and the communication technologies – SMTP, FTP, HTTP
  10. 10. Presentation Layer • Ensures communication between different data representations – ASCII, EBCDIC, JPEG, MPEG, GIF
  11. 11. Session Layer • Establishes, maintains and terminates sessions between applications – SQL, RPC
  12. 12. Transport Layer • Provides reliable, transparent transfer of data between end points – TCP, UDP
  13. 13. Network Layer • Provides routing and forwarding functionalities – IP, DHCP
  14. 14. Data Link Layer • Provides reliable transfer of information across the physical link – Ethernet, Token Ring
  15. 15. Physical Layer • Concerned with transmission of unstructured bit streams over physical medium – E1, T1
  16. 16. TCP/IP Model
  17. 17. Topologies
  18. 18. Wireless Networks
  19. 19. FHSS • Frequency Hoping Spread Spectrum – Takes the total bandwidth and splits it into smaller sub- channels
  20. 20. DSSS • Direct Sequence Spread Spectrum – Applies sub-bits to a message • The sub-bits are used to generate a different format of the data before the data are transmitted • The receiving end uses these sub-bits to reassemble the signal into the original data format
  21. 21. OFDM • Orthogonal Frequency Division Multiplexing
  22. 22. Data Link Layer • WLAN technologies and protocols Type Speed Frequency Modulation Description 802.11 1 Mbps 2.4 Ghz DSSS Legacy Protocol 802.11b 11 Mbps 2.4 Ghz DSSS First widely used protocol 802.11a 54 Mbps 5.0 Ghz OFDM Operated in 5 Ghz band 802.11g 54 Mbps 2.4 Ghz OFDM/DSSS 802.11n 150 Mbps 2.4 Ghz OFDM
  23. 23. Security Flaws • No user authentication • No mutual authentication • Flawed encryption protocol – Allows specific bits to be modified • Solution? – 802.11i • Incorporates security measures for the 802.11 standards!
  24. 24. WEP • Wired Equivalent Privacy – Used to provide confidentiality – Uses stream cipher RC4 – Versions • WEP-64 and WEP-128 – 24 bit IV – Authentication Methods • Open System Authentication • Shared Key Authentication
  25. 25. WEP • Open System Authentication – Any client, regardless of its WEP keys, can associate itself with the Access Point – No authentication (in the true sense of the term) occurs – After the association, WEP key needed for encrypting the data frames • At this point, the client needs to have the right key!
  26. 26. WEP • Shared Key Authentication – A four-way challenge-response handshake is used • Client sends an authentication request to the Access Point • Access Point replies with a clear-text challenge • Client encrypts the challenge text using configured WEP key, and sends it back to Access Point • Access Point decrypts the material, and compares it with the sent clear-text – Depending on the success of this comparison, the Access Point sends back a positive or negative response!
  27. 27. WPA • WiFi Protected Access – Uses Temporal Key Integrity Protocol (TKIP) • Adds 48 bit IV value • Implements a frame counter to discourage replay attacks! – Uses EAP via RADIUS Server • For authentication
  28. 28. WPA • WPA Modes – Enterprise Mode • Requires an authentication server • Uses RADIUS protocols for authentication and key distribution • Centralizes management of user credentials – Pre-Shared Key Mode • Does not require an authentication server • Shared secret is used for authentication • Device-oriented management
  29. 29. WPA2 • WiFi Protected Access 2 – Replaces TKIP with CCMP • Counter Mode with Cipher Block Chaining Message Authentication Code Protocol • Uses AES • Provides more robust security
  30. 30. Network Attacks
  31. 31. DNS Poisoning
  32. 32. SYN Flood
  33. 33. ARP Poisoning Request 140.252.13 .1 .2 .3 .4 .5 08:00:20:03:F6:42 00:00:C0:C2:9B:26 Reply 140.252.13 .1 .2 .3 .4 .5 08:00:20:03:F6:42 00:00:C0:C2:9B:26 arp req | target IP: 140.252.13.5 | target eth: ? arp rep | sender IP: 140.252.13.5 | sender eth: 00:34:CD:C2:9F:A0 00:34:CD:C2:9F:A0
  34. 34. Network Sniffing … telnet Router5 User Access Verification Username: squiggie password: Sq%*jkl[;T Router5>ena Password: jhervq5 Router5# Got It !! Router5
  35. 35. IP Spoofing A B C Attacker
  36. 36. DDOS Attack Attacker Innocent handler Victim A Innocent handler Innocent agents Innocent agents Attack Alice NOW !
  37. 37. Smurf Attack 172.15.0.0 Muddasar Yasir 1 ICMP Echo Req Src: Yasir Dest: 172.15.255.255 2 ICMP Echo Reply Dest: Dos Target
  38. 38. Virtual Private Networks
  39. 39. Introduction • A private network that uses a public network to connect remote sites or users together!
  40. 40. Concept
  41. 41. Features of VPN • Security • Reliability • Scalability • Network management • Policy management
  42. 42. VPN Concepts • Encapsulation – Inclusion of one data structure within another structure • Encryption – Hiding of real information • Tunneling – Virtual path that delivers a packet
  43. 43. Tunneling Protocols • PPTP • L2F • L2TP • IPSec
  44. 44. PPTP • Point to Point Tunneling Protocol – Designed for client/server connectivity – Sets up a single point-to-point connection between two computers – Works at the data link layer – Transmits over IP networks only
  45. 45. L2F • Layer 2 Forwarding – Created before L2TP by Cisco – Merged with PPTP, which resulted in L2TP – Provides mutual authentication – No encryption
  46. 46. L2TP • Layer 2 Tunneling Protocol – Hybrid of L2F and PPTP – Sets up a single point-to-point connection between two computers – Works at the data link layer – Transmits over multiple types of networks, not just IP – Combined with IPSec for security
  47. 47. IPSec • Internet Protocol Security – Handles multiple connections at the same time – Provides secure authentication and encryption – Supports only IP networks – Focuses on LAN-to-LAN communication rather than user- to-user – Works at the network layer, and provides security on top of IP – Can work in tunnel mode, meaning the payload and the header are protected, or transport mode, meaning only the payload is protected
  48. 48. Benefits of VPN • Extend geographic connectivity • Improve security • Improve productivity • Simplify network topology • Provide global networking opportunities • Provide broadband networking compatibility • Provide faster ROI (return on investment) than traditional WAN
  49. 49. Intrusion Detection Systems
  50. 50. Introduction • A system that detects and logs – Inappropriate, Incorrect, or Anomalous activity
  51. 51. Types • Network based IDS • Host based IDS
  52. 52. Methods • Pattern matching – Signature based • Anomaly detection – Checks any abnormality • Protocol behavior – Checks correct usage of protocol
  53. 53. Events • True positive – When the IDS sets off an alert and it is a real attack • True negative – When the IDS does not set off an alert and it is normal traffic • False positive – When the IDS sets off an alert and it is normal traffic • False negative – When the IDS does not set off an alert and it is attack traffic
  54. 54. Firewalls
  55. 55. Introduction • A system that prevents unauthorized access – To or from a network • Controls the flow of traffic
  56. 56. Concept
  57. 57. Firewall Types • Packet filtering firewall • Proxy firewall – Application level proxy – Circuit level proxy • Stateful inspection firewall • Dynamic packet filtering firewall • Kernel proxy firewall
  58. 58. Packet Filtering Firewall • Governed by set of directives • Works at network layer • Makes decisions on – Packet’s source IP Address – Packet’s destination IP Address – Network and transport protocol being used – Source and destination ports – The interface being traversed
  59. 59. Packet Filtering Firewall • Ingress Filtering – Blocking inbound traffic • Egress Filtering – Blocking outbound traffic
  60. 60. Application Level Proxy • Contains a proxy agent • Does not allow a direct communication • Operates at the application level • Inspects the content, payload and header! • Can require authentication from the user
  61. 61. Circuit Level Proxy • Creates a circuit between client and the server • Works at session layer • Knows the source and destination addresses and makes access decisions based on the header information • Faster than application level proxy
  62. 62. Stateful Inspection Firewall • Tracks the state of connections • Blocks packets deviating from expected state • Works same as packet filtering firewall but keeps a state table as well! • Works at network and transport layer
  63. 63. Dynamic Packet Filtering
  64. 64. Kernel Proxy Firewalls • Fifth generation firewall! • Creates dynamic, customized TCP/IP stacks for packet evaluation • When a packet arrives, a new virtual network stack is created, which is made up of only the protocol proxies necessary to examine this specific packet properly • Speed of Packet filtering firewalls
  65. 65. Firewall Architectures • Screening Router • Dual Homed Gateways • Screened Host Gateways • Screened Subnet
  66. 66. Screening Router
  67. 67. Screening Router • Screening Router – A router placed between trusted and public networks – Security policy implemented using ACLs – Advantages: • Inexpensive • Simple and completely transparent – Disadvantages • Limited logging functionality • Single point of failure • Uses no user authentication
  68. 68. Dual Homed Gateway
  69. 69. Dual Homed Gateways • A single computer with separate NICs connected to each network • Used to divide internal trusted network from external networks • Advantages: – Operates in a Fail Secure mode – Logging functionality • Disadvantages: – Inconvenience to users – Slower network performance
  70. 70. Screened Host Gateways
  71. 71. Screened Host Gateways • Employs external screening router and internal bastion host • Advantages: – Provides distributed security between two devices – Restricted inbound/outbound access • Disadvantages: – Multiple single point of failures
  72. 72. Screened Subnet
  73. 73. Screened Subnet • Deploys external screening router, internal bastion host and internal screening router • Concept of DMZ • Advantages: – Provides defense in depth • Disadvantages: – Difficult to configure and maintain – Difficult to troubleshoot
  74. 74. Unified Threat Management • Single system with all the solutions • Contains firewall, malware detection and eradication, sensing and blocking of suspicious network probes, and so on… • Requires lot of resources • Reduces network complexity
  75. 75. Why Firewall Security • Remote login • Application backdoors • Operating system bugs • Denial of service • Spam • Source routing
  76. 76. Best Practices • Change the default configurations • ACLs should be simple and direct • Disallow source routing • Close unnecessary ports with dangerous services • Disable unused interfaces • Block directed IP broadcasts • Block incoming packets with internal address (they are spoofed) • Enable logging • Daily checks to ensure security
  77. 77. Thank You!  • Any Questions?
  78. 78. Questions
  79. 79. Question 1 • Which of the following is not a security goal for remote access? A. Reliable authentication of users and systems B. Protection of confidential data C. Easy to manage access control to systems and network resources D. Automated login for remote users
  80. 80. Question 1 • Which of the following is not a security goal for remote access? A. Reliable authentication of users and systems B. Protection of confidential data C. Easy to manage access control to systems and network resources D. Automated login for remote users
  81. 81. Question 2 • Which of the following is the biggest concern with firewall security? A. Internal hackers B. Complex configuration rules leading to misconfiguration C. Buffer overflows D. Distributed denial of service (DDOS) attacks
  82. 82. Question 2 • Which of the following is the biggest concern with firewall security? A. Internal hackers B. Complex configuration rules leading to misconfiguration C. Buffer overflows D. Distributed denial of service (DDOS) attacks
  83. 83. Question 3 • Which of the following should NOT normally be allowed through a firewall? A. SNMP B. SMTP C. HTTP D. SSH
  84. 84. Question 3 • Which of the following should NOT normally be allowed through a firewall? A. SNMP B. SMTP C. HTTP D. SSH
  85. 85. Question 4 • Which type of attack involves the alteration of a packet at the IP level to convince a system that it is communicating with a known entity in order to gain access to a system? A. TCP sequence number attack B. IP spoofing attack C. Piggybacking attack D. Teardrop attack
  86. 86. Question 4 • Which type of attack involves the alteration of a packet at the IP level to convince a system that it is communicating with a known entity in order to gain access to a system? A. TCP sequence number attack B. IP spoofing attack C. Piggybacking attack D. Teardrop attack
  87. 87. Question 5 • Which of the following statements pertaining to packet filtering is incorrect? A. It is based on ACLs B. It is not application dependant C. It operates at the network layer D. It keeps track of the state of a connection
  88. 88. Question 5 • Which of the following statements pertaining to packet filtering is incorrect? A. It is based on ACLs B. It is not application dependant C. It operates at the network layer D. It keeps track of the state of a connection
  89. 89. Question 6 • What is the main characteristic of a multi- homed host? A. It is placed between two routers or firewalls B. It allows IP routing C. It has multiple network interfaces, each connected to separate networks D. It operates at multiple layers
  90. 90. Question 6 • What is the main characteristic of a multi- homed host? A. It is placed between two routers or firewalls B. It allows IP routing C. It has multiple network interfaces, each connected to separate networks D. It operates at multiple layers
  91. 91. Question 7 • One drawback of Application Level Firewall is that it reduces network performance due to the fact that it must analyze every packet and: A. Decide what to do with each application B. Decide what to do with each user C. Decide what to do with each port D. Decide what to do with each packet
  92. 92. Question 7 • One drawback of Application Level Firewall is that it reduces network performance due to the fact that it must analyze every packet and: A. Decide what to do with each application B. Decide what to do with each user C. Decide what to do with each port D. Decide what to do with each packet
  93. 93. Question 8 • Address Resolution Protocol (ARP) interrogates the network by sending out a? A. Broadcast B. Multicast C. Unicast D. Semicast
  94. 94. Question 8 • Address Resolution Protocol (ARP) interrogates the network by sending out a? A. Broadcast B. Multicast C. Unicast D. Semicast
  95. 95. Question 9 • As a result of a risk assessment, your security manager has determined that your organization needs to implement an intrusion detection system that can detect unknown attacks and can watch for unusual traffic behavior, such as a new service appearing on the network. What type of intrusion detection system would you select? A. Protocol anomaly based B. Pattern matching C. Stateful matching D. Traffic anomaly-based
  96. 96. Question 9 • As a result of a risk assessment, your security manager has determined that your organization needs to implement an intrusion detection system that can detect unknown attacks and can watch for unusual traffic behavior, such as a new service appearing on the network. What type of intrusion detection system would you select? A. Protocol anomaly based B. Pattern matching C. Stateful matching D. Traffic anomaly-based
  97. 97. Question 10 • What refers to legitimate users accessing networked services that would normally be restricted to them? A. Spoofing B. Piggybacking C. Eavesdropping D. Logon abuse
  98. 98. Question 10 • What refers to legitimate users accessing networked services that would normally be restricted to them? A. Spoofing B. Piggybacking C. Eavesdropping D. Logon abuse
  99. 99. Thank You! 

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