Network security.
Lecture 13
What is Network security ?
Network security consists of the technologies and
processes that used to protect networks from
external threats.
The primary goal of network security is to provide
controls at all points along the network perimeter
which allow access to the network and only let traffic
pass if that traffic is authorized.
Network Security Risks
- Denial of Service :
Attacks on the availability of networks or computer
systems.
- Information theft :
Attacks on confidential information (e.g., customer
private information, credit card information, etc.).
Network Security Risks
- Intrusion :
Unauthorized access to a network or computer system
that could compromise the integrity and/or
availability of critical systems and data
- Reputation :
Confidence of customers, business partners, etc. is lost.
This is perhaps the biggest risk that Businesses face.
Hackers
- Hacker is somebody who finds weaknesses in a
computer or computer network and exploits them
through a process called penetration.
- Hacker attempts to break into computer systems to
damage it, or for the purpose of getting illegitimate
access to resources.
Types of hacker:
1 - White Hat :A white hat hacker is someone who has
non-malicious intent whenever he breaks into security
systems and whatnot.
2 - Black Hat :A black hat hacker, also known as a cracker, is
the type of hacker that has malicious intent whenever he
goes about breaking into computer security systems with
the use of technology such as a network, phone system,
or computer and without authorization.
3 - Grey Hat :A grey hat hacker is someone who exhibits
traits from both white hats and black hats.
Hackers
How can hackers break into computer system ?
- Hackers gain access to your computer through
weaknesses in your system. Usually they use a
selection of specialist software to identify weaknesses,
like sub seven , Net Bus … etc.
- To get their intermediate base they use purpose built
programs called Trojans and backdoors. It may be
disguised as a game or some other kind of executable
program.
Network viruses
- A network virus is a self-contained program (or set of
programs) that can spread copies of itself across
networks, including the Internet.
- In many cases, network viruses exploit vulnerabilities
in the operating system or other installed programs
to spread.
- Some of the most famous network viruses are
Nimda and SQLSlammer .
Network viruses
Nimda is a virus that caused traffic slowdowns across
the Internet, it quickly spread within 22 minutes .
Methods of infection:
- Via email.
- Via open network shares.
- Via browsing of compromised web sites.
Damages of network viruses
- Ability to quickly degrade the performance of a
network, totally disabling important devices, programs
and network connections and operating other
programs such as (dos)and even sending themselves
over the internet via emails or attachment.
- Once the infection spreads, fully Elimination often
becomes difficult.
Security Technologies
- Physical security.
- Authentication technologies.
- Firewalls.
- Cryptography.
Physical security
- Physical Access Controls.
There are many types of physical access controls
including :- Badges.
- Guards.
- Keys and locks.
- Intrusion detectors, such as television cameras,
motion detectors, and other devices.
Authentication technologies
Authentication technologies associate a user with a
particular identity. People are authenticated by three basic
means:
- by something they know (e.g., PIN number or password)
- by something they have (e.g., key, smart card), or
- by something they are such as a biological characteristic
(e.g., fingerprint, retinal signature)
Firewall
A firewall is a software or hardware-based network
security system that controls the incoming and outgoing
network traffic by analyzing the data packets and
determining whether they should be allowed through or
not, based on applied rule set.
Cryptography
- The art of protecting information by transforming it
(encrypting it) into an unreadable format, called cipher
text. Only those who possess a secret key can
decipher (or decrypt) the message into plain text.
- An encryption algorithm is a method of encryption and
decryption.
Cryptography
Example:
Alice wants to send a message to Bob that nobody else
can read.
Wireless Network Security
- Wireless security is the prevention of unauthorized
access or damage to computers using wireless
networks.
- The most common types of wireless security are :
- Wired Equivalent Privacy (WEP) .
- Wi-Fi Protected Access (WPA).