Transcript Presentation on the Network security

presentation
on
security issues in
networking
Presented by:
Ayesha Yasin
Nazish Yaqoob
Kiran Shakoor
Razeena Ameen
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What is network
security?
In simple words ,security has been
defined as “protecting information
system from unauthorized access”
Network security is defined as the
proper safeguarding of all components
associated with the network, including
data, media, hardware, software and
networks.
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Fundamental concepts
of network security:
Objectives of network security
Threats of network security
Safeguards
Attacks on network
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Objectives of network
security
Network security has three major
objectives are given below
Confidentiality: Ensuring that
information is not disclosed or revealed
to unauthorized persons.
Integrity:Assurance that data is not
altered or destroyed in an unauthorized
manner
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Legitimate use:
Ensuring that authorized
persons don’t use the information in an
unauthorized way.
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Threats of network
security
Threats include in the network security :
Viruses:Computer programs written by
programmers and designed to replicate
themselves and infect computers when triggered
by a specific event
Trojan horse programs : Delivery vehicles for
destructive code, which appear to be harmless or
useful software programs such as games
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Vandals:Software applications or
applets that cause destruction
Eavesdropping:It is leakage of information
by monitoring communication channels
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Information leakage: Information is
revealed to unauthorized users which is
threat to secrecy
Repudiation: A person participating in an
exchange of information denies having
participated
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Authorized Violation: A person
authorized to use resources uses it in
unauthorized way
.
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Safeguards
Safeguards are physical controls
,security policies and procedures that
protect networks from threats.
The following types of the safeguards
are used in the network security
Scanners: Most antivirus software is a
scanner, which scans viruses
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Behavior blockers: This utility remains in
the memory and alerts the user of any
suspicious activity
Identifying services:These services help
to identify users and control their activities
and transactions on the network. Services
include passwords,digital certificates,
and digital authentication keys.
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Attacks on network
:
There are different types of attacks
Viruses and worms
IP spoofing:The attacker changes the IP
address on message packets to that of
another user or host machine
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Brute force attacks :An attacker tries
all possible passwords ,one at a time in the
hope to uncover the correct password
Denial of service attack:
attacks occurs when servers are flooded with
recursive queries in an attempt to prevent the
server from servicing client requests. A
successful DoS attack can result in the
unavailability of services, and in the eventual
shut down of the network
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Man in the middle:A man-in-the-middle
(MITM) attack occurs when a hacker
eavesdrops on a secure communication
session and monitors, captures and
controls the data being sent between
the two parties which is communicating
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What is a firewall?
A device installed between the internal
network of an organization and rest of
the internet to provide security.
A firewall is a combination of hardware
or software that sits between the
internet and internal organization to
protect the network from outside attack.
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What can be a firewall?
A firewall can be a router, PC, a server
or a collection of such devices.
It may be a hardware device or a
software program running on a secure
host computer.
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Functions of a firewall
Three major functions of firewall are
1) Examine data
2) Filter data
3) Protect network from attacks
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Types of firewalls
There are five generally accepted types of
firewalls used on internet connections:
1) Frame-filtering firewalls
2) Packet-filtering firewalls
3) Circuit gateway firewalls
4) “Stateful” firewalls
5) Application gateways or proxies firewalls
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Frame-filtering Firewalls
A frame-filtering firewall has the ability
to filter to the bit level layout.
By providing filtering at this level frames
that do not belong on the trusted
network are rejected before they reach
anything valuable even on the firewall
itself.
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Packet-filtering firewalls
A packet-filtering firewall is either a router
with packet-filtering capabilities or a
dedicated devices that does packet-filtering.
It operate on the data link and network layers.
Following fields within packets can be filtered:
1) The type of the packet such as IP,TCP,UDP.
2) IP source and destination address.
3) TCP/UDP sources and destination ports.
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Packet filtering
inspects each
packet passing
through the network
and accepts or
rejects it based on
user-defined rules.
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Circuit gateway
firewalls
A circuit gateway firewall typically involves the
session setup between a system and the
user security options relative to that system
for a particular user.
It check the user IDs and password for a
connection request.
Circuit firewalls are also responsible for
logging who came from where and went to
what.
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This is useful for hiding information
about protected networks.
It can cut of any connection which is
hijacked by a hacker trying to pass
through the firewall.
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“Stateful” firewalls
•
•
•
This firewall combines the aspects of the
other three types of firewalls.
It is concerned with the need to examine
the transaction condition between two
interoperating applications becomes
essential to defeating certain sophisticated
types of network attacks.
This type of firewall can help prevent
attacks which exploit existing connections,
or certain Denial-of-service attacks.
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Information traveling from inside the
firewall to the outside is monitored for
specific defining characteristics, then
incoming information is compared to
these characteristics.
If the comparison yields a reasonable
match ,the information is allowed
through. Otherwise it is discarded.
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Application gateways or
proxies firewalls
It provides protection at the application
level.
It applies security mechanisms to
specific applications, such as FTP and
Telnet servers.
In principle application firewalls can
prevent all unwanted outside traffic from
reaching protected machines.
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In contrast to packet filter firewall it filter
the request rather than packets entering
or leaving the network.
It can block any FTTP or HTTP request.
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Cryptography
Cryptography is technique of converting
a message into un-understandable form
such that even if some unauthorized
person intercepts the message he
would not be able to make any sense
out of it
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Encryption
The process of encoding a message
Decryption
The process of decoding a message
Unencrypted data is referred as plain
text
Encrypted data is called cipher text
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Traditional way of
cryptography
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Secret key cryptography
With ,secret key cryptography a single key is used
for both encryption and decryption. the sender
uses the key to encrypt the plaintext and sends the
cipher text to the receiver. The receiver applies the
same key to decrypt the message and recover the
plaintext. Because a single key is used for both
functions, secret key cryptography is also called
symmetric cryptography.
With this form of cryptography, it is obvious that
the key must be known to both the sender and the
receiver; that, in fact, is the secret.
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Public key cryptography
In public key cryptography two keys are
used one is public key which is
available to everyone is used to encrypt
message. Other is private key which
remains secret and is not given to
anyone, is used to decrypt message
Also called asymmetric cryptography
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Authentication and
access control
Authentication is a security measure. it
is a process of verifying a claimed
identity. the concept of authentication is
similar to providing someone access to
a secure area
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Three authentication
measures
Digital certificate
Smart card
Kerberos
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Digital certificates
An attachment to an electronic message used for
security purposes. The most common use of a digital
certificate is to verify that a user sending a message
is who he or she claims to be, and to provide the
receiver with the means to encode a reply. An
individual wishing to send an encrypted message
applies for a digital certificate from a Certificate
Authority (CA). The CA issues an encrypted digital
certificate containing the applicant's public key and a
variety of other identification information
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The CA makes its own public key readily
available through print publicity or perhaps on
the Internet.
The recipient of an encrypted message uses
the CA's public key to decode the digital
certificate attached to the message, verifies it
as issued by the CA and then obtains the
sender's public key and identification
information held within the certificate. With
this information, the recipient can send an
encrypted reply.
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Smart card are similar
to credit card, a smart
card has integrated
circuit embedded in it.
It use identification
numbers, biometric
(fingerprints, voice,
signature) to
authenticate a user.
smart card can be used
as cash card, telephone
card, credit card etc
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Kerberos
Kerberos uses three –pronged
approach for authentication
Database (contains user’s rights)
Authentication server
Ticket granting server
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How it works
Let’s assume we want to access a data file stored on
one of our company server. when we first log on and
request access to this file, an authentication server
searches its database for our access right. when
server confirms that we have permission to access
these files, it generates an encrypted ‘ticket’ which
enables our workstation to access ticket-granting
server. the authentication server also returns key
which was used to encrypt message called
‘authenticator’ our workstation then sends ticket and
authenticator to ticket granting server
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Which decrypt both pieces of data. if they
match, ticket-granting server generates
a ticket for the requested service to be
used only by us. this ticket is then
returned to our workstation, which we
present to company’s server on which
file is stored. when server receives our
ticket, it gives access to the file
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