Network Security

1. Network Security

2. Network Security Network security comprises authentication and encryption Authentication is typically accomplished through a user name and password Other forms of authentication are digital certificates, smart cards, and biometrics

3. 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 For sake of clarity, the textbook uses term intruder

4. 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

5. 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 Jgullibleand my Password is toocool

6. 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

7. 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

8. 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

9. 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 attack Using an IP or MAC address from a previous network transmission to make an unauthorized connection.

10. Spoofing Example: Using a valid IP address to fool a server Example: Using a bogus IP address and ID when sending unsolicited e-mail

11. 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

12. Trojan Horse Example: Free download that contains malicious code That code could contain virus, worm, or backdoor Example: Can imitate legitimate logon screen When user logs on, name and password are sent to unauthorized user

13. E-Mail Attachments Source of most commonly encountered viruses Malicious code can be programmed into attachment When recipient opens attachment, malicious program is activated

14. Applied Networking 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?

15. 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

16. 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

17. 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

18. Applied Networking 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?

19. In class lab Roberts 72 & 73 Next Class November 6th, 2013 Labsim Homework 8.2.2-8.2.4