1. Network Security

2. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Objectives  Give examples of common network security breaches and vulnerabilities.  Differentiate between symmetrical and asymmetrical encryption.  Recall the role of a Certificate Authority (CA).  Compare RADIUS and TACACS+.  Compare authentication protocols.

3. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Objectives  Summarize the characteristics of a secure password.  Give examples of how a firewall can be used to secure network access.  Recall the purpose of various computer and network security tools.

4. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Network Security  Network security comprises authentication and encryptionauthentication  Authentication is typically accomplished through a user name and password  Other forms of authentication are digital certificates, smart cards, and biometrics

5. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Hackers, Crackers, and Intruders  Exact meaning of hacker depends on the context in which it is used and by whom  Cracker typically means anyone who gains access to a computer system with intent to do harm or play pranks Cracker  For sake of clarity, the textbook uses term intruder

6. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Unprotected Network Shares  Network shares with minimal or no security plus remote access enabled on a computer are a security breach waiting to happen  Hacker tools can probe and access available network shares

7. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Social Engineering  Relies on the gullibility of a network user and his or her respect for authority  Caller: Hello. This is Bob down at IMS operations conducting as security check. We believe we may have an intruder in our system.  Joe Gullible: Yes. What Can I do To help ?  Caller: Well Joe, I need to look at your PC files to see if there have been any possible intrusions. I need your username and password.  Joe Gullible : Sure. My username is Jgullible and my Password is toocool

8. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Open Ports  Common way for intruders to gain access to a system  Administrators should close all unused ports  Third-party utility or the netstat utility can be used to check for open ports

9. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Zero Configuration (Zeroconf)  Standard Developed by the IEEE  Advantage  Enables a network device to automatically configure itself for a network  Disadvantage  Makes a network less secure

10. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Denial of Service (DoS)  One of the most common attacks on a server  Can overload a server to the point that it crashes or is not able to complete a legitimate user request

11. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Man in the Middle (MITM)  Intruder intercepts network transmission, reads it, then places it back on route to its destination  Contents may or may not be modified  MITM can also be used for a replay attackreplay attack  Using an IP or MAC address from a previous network transmission to make an unauthorized connection.

12. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Spoofing  Example: Using a valid IP address to fool a server  Example: Using a bogus IP address and ID when sending unsolicited e-mail

13. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Smurf Attack  A type of DoS  To deal with a DoS attack  Configure the computer firewall not to respond to ICMP (Internet Control Message Protocol) echo requests  Configure routers not to forward ICMP echo requests to broadcast addresses in the network

14. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Trojan Horse  Example: Free download that contains malicious code  That code could contain virus, worm, or backdoorbackdoor  Example: Can imitate legitimate logon screen  When user logs on, name and password are sent to unauthorized user

15. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. E-Mail Attachments  Source of most commonly encountered viruses  Malicious code can be programmed into attachment  When recipient opens attachment, malicious program is activated

16. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. As a network administrator, you are in charge of educating company employees on the dangers of e-mail attachments. What might you tell the employees concerning e-mail attachments and the prevention of infecting their computers and the network with malware? Applied Networking

17. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Macro Virus  Series of common keystrokes can be linked to a virus  Can be sent as e-mail attachment and is launched when recipient opens attachment  May infect a template file like normal.dot and then execute when user presses a certain combination of keys

18. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Worm  Most common worm programs use e-mail to replicate and spread to other computers  Common safeguard against worms is setting up a dedicated mail server

19. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Phishing  E-mail can appear as if it’s from a legitimate company, such as a credit card company  E-mail requests user’s personal information, such as social security number or bank account PIN  Phony web sites that look authentic, but have slightly different domain names

20. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. As a network administrator, you are in charge of educating company employees on the dangers of phishing. What might you tell the employees concerning detecting and handling a phishing attack? Applied Networking

21. I N CLASS LAB Roberts 72 & 73 N EXT C LASS November 6 th, 2013 Labsim Homework 8.2.2-8.2.4