Network Security

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 authentication The 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 Station1 3. Station1 uses private key to encrypt message 4. Station1 sends encrypted message to Station2 5. 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

Independent Computer Architecture (ICA) Citrix ICA and Microsoft Remote Desktop Protocol are the two main choices for this type of application

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 website Labsim 8.25 Next Class No class on Monday November 11th, 2013 November 13th, 2013 Labsim Homework 8.3.1–8.3.3