network security philosophy &...
TRANSCRIPT
2/24/15 Dr. Enis Karaarslan 1
Network SecurityPhilosophy & Introduction
Dr. Enis Karaarslan
Muğla University
Computer Engineering
Department
Netseclab.mu.edu.tr
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SECURITYPHILOSPHY
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Computer & Network Security has similarities with the security in normal life.
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There is no such thing as %100 Security
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Security at the gates only, is not enough
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A chain is only as strong as its weakest link
As there is no %100 security …So give up?
A possible solution:Use more than one chain
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MULTI LAYER SECURITY
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Security x Usability
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Value of Assets and Expenditures
What is the VALUE of your asset (data, prestige …)?
Keep in mind that Security expenditures should not be
greater than the value of the assets
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Risk Analysis
Risk analysis is essential If the risk is too low, that/some
precaution(s) can be cancelled …
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False Sense of Security
A “false sense of security” is worse than “a true sense of insecurity”.
Solution:Never think your system is secure.
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No Template Which Suits All
There is no templates which suits all. There is a different solution for
different organizations• Different needs• Different assets
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To win a war,one must know the way
Sun TzuThe Art of War
Security is a process, not a product.Bruce Schneier
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MONITOR
The system should be monitored for intrusions
And immediate action should be taken at attacks
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Warn The Attacker
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Try to Buy time for …
Make attacking difficult for … • Discovery of the attack• Take measures
Make decryption difficult so that• The data is not valid or valuable any
more.
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Network Awareness
Know your enemy (?) Know yourself,
• know your assets• know what to protect
Know your systems more than the attacker
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FUNDAMENTALS
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INFORMATION SYSTEM
Information System and Security
ATTACKER
VULNERABILITY
ATTACK
USERS
SECURITYMEASURES
Vulnerable Systems
The systems are vulnerable• Mainly because of bad coding• Must be patched (but can not be done
rapidly as they should)• False sense of security
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A vulnerability timeline …
The Attacker/Intruder
The attacker can be called as:Lamer, intruder, attacker … (wrongly used as hacker also)
Also secret organizations? Also companies(serious antivirus/defence economy)
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Hacker /Lamer /Attacker …
Hacker is used as attacker/lamer, in the meaning:
The intruder, who gets in your system and intends to use for his/her own aims.
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The Attacker
The attackers strength is Dedication• Will not stop until he/she gets in• Can use the computer for days long sleepless• Knows the vulnerabilities of systems
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Network Security Assets
Network Security Overall• Network Awareness• Firewall, Intrusion Detection Systems … etc• More …
Host (Computer/Server/NW Device) Security• Physical Security
• OS and Application Security• User Management
Encryption
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Firewall
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Firewall Basics
Rule based access control between networks.
Software/hardware based Architecture
• Static Packet Filtering• Dynamic Packet Filtering (Statefull
inspection)• Application Level Protection
Logging and alert capabilities
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Encryption
Encryption is the conversion of data into a form, called a ciphertext, that cannot be easily understood by unauthorized people.
(Encryption x Decryption)
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Encryption Two different methods (according to key use)
• Conventional– Two keys are the same• Asymetric – (Public Key Encryption) –
Key pair (public, private)
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Encryption
To decyrpt an encrypted data• How much time?• How much Processing (Computing power)?
The science which deals with encryption is Cryptology