Network Security. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Intrusion Detection and Intrusion Prevention

Network Security

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.

Intrusion Detection and Intrusion Prevention Systems

Intrusion Detection System (IDS)—Only detects unauthorized activity. Example: MS Event Viewer

Intrusion Prevention System (IPS)—Detects unauthorized activity and performs some function to stop the activity. Example: Most antivirus software

IDS and IPS require some form of port monitoring When a particular port on a switch is connected directly to the IDS or IPS and monitors all activity through another port on the same switch.


Public Key Infrastructure (PKI)

Provides encryption and authenticationThe method of using an algorithm to encode data. Algorithm converts data into ciphertext

encrypted data Cryptology—Science of encrypting data Generates key and uses it for encryption Generates certificate to verify authentication


Key Encryption Methods

Symmetric-key encryption—Generally used when large amounts of data need to be encrypted

Asymmetric-key encryption—Both the public and private keys are needed to encode and decode data


Digital Certificate

A file that commonly contains data such as

the user’s name and e-mail address, the public key value assigned to the

user, the validity period of the public key, issuing authority identifier information


Certificate Authority (CA)

1. Station1 applies for digital certificate from a CA to send an encrypted message to Station2

2. CA issues digital certificate to Station13. Station1 uses private key to encrypt message4. Station1 sends encrypted message to Station25. Station2 uses the public key to decode

encrypted message


Details of a VeriSign Digital Certificate


Security Sockets Layer (SSL) and Transport Layer Security (TLS)

Application layer protocols Support VoIP, e-mail, and remote connections Based on public key encryption technology Displays https:// when securing Web site

connection Not compatible with each other TLS more secure; SSL more popular


Secure HTTP (S-HTTP)

Uses symmetric, or private, keys for encoding and decoding messages

Not supported by all Web browsers


Virtual Network Connection (VNC)

Describes point-to-point connection to a remote device

Connection considered “virtual” because user’s network device is not a physical part of remote network


Internet Protocol Security (IPSec)

Collection of security protocols, hashes, and algorithms

Authentication can be verified with Kerberos, a preshared key, or digital certificates

IPSec VPNs typically use public and private keys for encryption


IPSec Modes

Transport mode An IPSec mode that only encrypts the payload.

Tunnel mode An IPSec mode that encrypts the payload and the header.


Secure Shell (SSH)

Originally designed for UNIX to replace Remote Login (rlogin), Remote Shell (rsh), and Remote Copy (rcp)

Uses port 22 Requires a private key, public key, and password Can be used on operating systems that support

TCP/IP


SSH Example


Secure Copy Protocol (SCP)

Replacement for rcp command Does not require password


Service Set Identifier (SSID)

Identifies wireless network Similar to workgroup name All wireless network devices are configured with a

default SSID To secure the wireless network, the default SSID

should be changed


Media Access Control (MAC) Filtering

To configure MAC filtering, administrator creates an Access Control List (ACL)

ACL is located on Wireless Access Point (WAP) ACL contains list of MAC addresses belonging to

authorized wireless network devices


Wired Equivalent Privacy (WEP)

First attempt to secure with encryption the data transferred across a wireless network

Algorithm not complex and can be easily cracked A VPN can add to the security set in place by

WEP


Wi-Fi Protected Access (WPA)

Developed by the Wi-Fi organization to overcome the vulnerabilities of WEP

Compatible with 802.11 devices Wi-Fi Protected Access 2 (WPA2) is an enhanced

version of WPA WPA2 is compatible with the 802.11i standard


802.11i

IEEE ratified 802.11 standard to remedy original security flaws

Specifies the use of a 128-bit Advanced Encryption Standard (AES) for data encryption

Generates fresh set of keys for each new connection

Downward compatible with existing 802.11 devices


802.1x Authentication

Provides port-based, network access control Used for client/server-based networks Supplicant—Wireless network device requesting

network access Authenticator—WAP provides authentication Authentication server—Server running Remote

Authentication Dial-In User Service (RADIUS)

IN CLASS LAB

Languard Lab – download lab from course websiteLabsim 8.25

NEXT CLASS

No class on Monday November 11th, 2013November 13th, 2013 Labsim Homework 8.3.1–8.3.3

Documents

Network Security. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Intrusion Detection and Intrusion Prevention