Presentation on Network Security.

1. Network Security
By Gaurav Dalvi
Final Yr BTech
Roll no:A43
Reg
no:2011BCS501

2. Why Security?
 The Internet was initially designed for
connectivity.
 Fundamental aspects of information must be
protected.
 We can’t keep ourselves isolated from the
Internet.

3. Internet Evolution
•Different Ways to handle security as the Internet
Evolves.

4. Type Of Security
 Computer Security
generic name for the collection of tools designed
to protect data and to thwart hackers
 Network Security
measures to protect the data during the
transmission.
 Internet Security
measure to protect the data during the
transmission over a collection of interconnected
networks.

5. Goals of Information Security

6. Attacks on Different Layers

7. Security on Different Layers

8. IP
 IP is a network layer protocol.
 This is a layer that allows the hosts to actually
“talk ” to each other.
 IP has a number of very important features which
make it an extremely robust and flexible protocol.

9. Attacks on IP
 Attacks exploits the fact that IP does not perform
a robust mechanism for authentication, which is
proving that the packet came from where it claims
it did.
 This means that the host authentication must be
provided by higher layers.
 Eg: IP Spoofing, IP Session hijacking.

10. TCP Attacks
 Exploits TCP 3-way handshake.
 Attacker sends a series of SYN packets without
replying with the ACK packet.
 Finite queue size for incomplete connections.

11. TCP Attacks

12. DNS Cache Poisoning

13. Common Type of Attacks
 Ping sweeps and port scans – reconnaissance.
 Sniffing – capture packet as they travel through




the network.
Man in the Middle Attack – intercept messages
that are intended for a valid device.
Spoofing – set up a fake device and trick others
to send messages to it.
Hijacking – take control of a session.
Denial of Service (DoS) and Distributed DoS
(DDoS).

14. Trusted Network
 Standard defensive-oriented technologies.
- Firewall – first line of defense.
- Intrusion Detection.
 Built trust on the top of the TCP/IP infrastructure.
- Strong Authentication.
- Two factor authentication.
- something you have + something you
know.
- Public key Infrastructure.(PKI)

15. Firewall
 A choke point of control and monitoring.
 Interconnects networks with differing trust.
 Imposes restrictions on network services.
 only authorized traffic is allowed.
 Auditing and controlling access.
 can implement alarms for abnormal behavior.
 Itself immune to penetration.
 Provides perimeter defence.

16. Intrusion Detection System
An intrusion detection system (IDS) is a device
or software application that monitors network or
system activities for malicious activities or policy
violations and produces reports to a management
station. Some systems may attempt to stop an
intrusion attempt but this is neither required nor
expected of a monitoring system.
 Host IDS.
 Network IDS.

17. Access Control
 Access Control – ability to permit or deny the use
of an object by a subject.
 It provides 3 essential services (known as AAA):
- Authentication.(who can login)
- Authorization.(what authorized user can do)
- Accountability.(identifies what a user did)

18. Cryptography
 Has evolved into a complex science in the field of
information security.
 Encryption – process of transforming plaintext to
ciphertext using a cryptographic key.
 Symmetric key cryptography.
- DES, 3DES, AES, etc.
 Asymmetric key cryptography.
- RSA, Diffie-Hellman, etc.

19. Cryptography

20. Public key Infrastructure
 Combines public key cryptography and digital
signatures to ensure confidentiality, integrity,
authentication, non-repudiation and access
control.
 Digital Certificate – basic element of PKI; secure
credential that identifies the owner.
 Basic Components:- Certificate Authority.
- Registry Authority.
- Repository.
- Archives.

21. Different Layers of Encryption

22. IPSec
 Provides Layer 3 Security.
 Tunnel or Transport mode.
- Tunnel mode(entire IP packet is encrypted)
- Transport mode (IPSec header is inserted into
the packet)
 Combine different components:
- Security associations, Authentication headers
(AH), Encapsulating security payload (ESP),
Internet Key Exchange (IKE).

23. Security Management
 Loss Prevention.
Loss prevention focuses on what your critical assets
are and how you are going to protect them.
 Security risk management.
Management of security risks applies the principles of
risk management to the management of security
threats.
 Risk options.
 Risk avoidance.
 Risk reduction.
 Risk spreading.
 Risk transfer.
 Risk acceptance.

24. Whois Database
 Public network Management Database.
 Tracks network Resources.
- IP addresses, ASN, reverse routing.
 Records administrative info.
- Contacts(person/role), authorization(maintainer)
 All members must register their resources in the
Whois database.
 Must keep records up to date at all times.