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OutlineWhat is network security?Why do we need security?Who is vulnerable?Common security attacks and countermeasures.How to secure routers and networks with routers.Wireless LAN(WLAN) and its security.

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What is Network security?• comprises the measures a company takes to

protect its computer system.• consists of the provisions

and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources.

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Why do we need security?

Confidentiality: only sender, intended receiver should “understand” message contents– sender encrypts message– receiver decrypts message– Privacy: hide `who is doing what with whom`

Authentication: sender, receiver want to confirm identity of each other

Integrity: sender, receiver want to ensure messages are not altered (in transit, or afterwards) without detection

Access and Availability: services must be accessible and available to users

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ConfidentialityProtecting sensitive

information from unauthorized disclosure or interception.

Integrity

Safeguarding the accuracy

and completeness

of information

AvailabilityEnsuring that

information and vital services are available to users

when required.

Information Security

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Who is vulnerable?• Financial institutions and banks• Internet service providers• Pharmaceutical companies• Government and defense agencies• Contractors to various government agencies• Multinational corporations• ANYONE ON THE NETWORK

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Common security attacks and their countermeasures

• Finding a way into the network– Firewalls

• Exploiting software bugs, buffer overflows– Intrusion Detection Systems

• Denial of Service– Ingress filtering, IDS

• TCP hijacking– IPSec

• Packet sniffing– Encryption (SSH, SSL, HTTPS)

• Social problems– Education

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Examples of some attacks

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Router security• router’s route tables• router’s access control• router filtering configuration • router cryptographic security

features

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Router Security cont..• Protecting the Router Itself:

Physical Security Operating SystemConfiguration Hardening : Unnecessary services

should be disabled in the router configuration. • Protecting the Network with the Router:

Packet Filters for TCP/IP Permit Only Required Protocols and Services Reject Risky Protocols and Services

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Router Security conti..Address Filtering

Reject all traffic from the internal networks that bears a source IP address which does not belong to the internal networks.

Reject all traffic from the external networks that bears a source address belonging to the internal networks.

Reject all traffic with a source or destination address belonging to any reserved, unroutable, or illegal address range.

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Managing the Router• Access Mechanisms for Administrators Local and remote Administration

Local – Console Remote – Telnet/SSH or SNMPv3

AAA servers(RADIUS or TACACS+) are being used for administration access control.• Updating the Router – operating system and configuration

file.• Logging • Operational Security Management: Maintaining the security

of a router over its operational lifetime requires regular assessment, testing, and correction.

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Wireless LAN and its security

Features of WLAN(IEEE802.11):• Networking based on radio waves rather than wired cables.• convenience especially for the cases when mobility is

required.• A good solution when short-term or emergency

connections are needed. • It is not as Secure, fast or reliable as wired network.

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Security Attacks Traffic Analysis Passive Eavesdropping Active Eavesdropping Unauthorized Access Man-in-the-middle Attacks Session High-Jacking Replay Attacks Rouge AP Dos Attacks

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Security measures Carefully select SSID to be unique and disable SSID broadcast mode. Configure MAC address filtering mechanism on Aps. Disable DHCP if any. Apply Best encryption mechanism supported by the AP.

WEP(Wired Equivalent Privacy) – Easy to break The Wi-Fi Protected Access (WPA and WPA2) security protocols were later created to

address the problems with WEP.

Locking down the AP – Disable administration access of AP from Wireless side.

Restricted access networks - The standard method of WLAN authentication uses the 802.1X protocol. If the protocol is enabled, unauthenticated users cannot get past the AP to access the rest of the network.

Enable VPN access only.

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Thank you

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