What Is Network Security?

What is Network Security?

1.1.1 Definition

 Ensure Network Integrity and Data Confidentiality

 Protect from External & Internal Malicious Attacks

 Monitor Potential Threats

1.1.2 Host vs Network Security

 Log/File/Registry Creation/Modification/Deletion Monitoring

 Process Start/Stop Monitoring

 Pros: Block Attack Attempt from Internal, Monitor Misuse of Authenticated User

 Cons: Single Point Management, Difficult to Install and Maintain

1.2 Type of Network Attacks

1.2.1 DoS(Denial of Service)

 Heavy Network Load

 Difficult to Track Attacker

 DDoS(Distributed DoS), Reflective DDoS

 Example

 IP Fragmentation

 TCP Segmentation

 Ping of Death

 TCP Port Scan

 Trinoo

1.2.2 Unauthorized Access

 Change Configuration

 Gain Root Privilege

 Execute Commands

 Data Destruction

 Get Information

 Example

 Slammer Worm

 Blaster Worm

 MyDoom Worm

 SQL Injection

1.5 History of Network Security

1.5.1 Packet Filtering Firewall (OSI)

 Enforce Access Policy

 Pros: Block Unauthorized Access, High Speed, Flexibility

 Cons: Layer 2~3 Based

1.5.2 Stateful Firewall (OSI)

 Track Session ( State of Connection )

 Stateful Inspection

 TCP Connections

 UDP, ICMP

 Pros: DoS(Denial of Service) Attack

 Cons: Layer2~4 Based

1.5.3 Application Firewall (OSI)

 Proxy

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