Lesson 10 – SECURING YOUR NETWORK

1. Lesson 10 – SECURING YOUR NETWORK

2. OVERVIEW • Security devices • Internal security • External security • Viruses and other malicious software

3. SECURITY DEVICES • Firewall: System enforcing security policy between two Networks.

4. Security devices • Proxy Server: Server acting as a proxy (an anonymous intermediary) for Network users.

5. Security devices • Packet filter: Enables users to set criteria for allowed and disallowed packets.

6. INTERNAL SECURITY Securing Network from internal threats like: • Accessing information inappropriately. • Accessing other users’ files. • Impersonating other users. • Performing criminal activities on systems. • Packet “sniffing” on the Network.

7. Internal security • Account security • File and directory permissions • Practices and user education

8. Account security • Process of managing the user accounts enabled on the Network.

9. Account security To manage security: • Remove the guest account. • Rename the default name for the administrative account. • Remove access to Network resources. • Work closely with HR/legal departments. • Review newly assigned permissions.

10. Account security To maintain password security: • Get users to change their Network password regularly. • Set the reuse policy. • Have passwords that are at least eight characters long. • Establish thresholds.

11. File and directory permissions • Control access to files and directories by using built-in permissions.

12. File and directory permissions Generic directory roles: • Create only • Read only • Change • Full control

13. Practice and user education • Inform users what is expected of them in terms of security. • Discuss security issues with new employees. • Have users acknowledge their understanding. • Periodically audit users’ security actions. • Review the NOS’ security logs.

14. EXTERNAL SECURITY • Process of securing the Network from external threats.

15. External security Types of threats: • Front-door threats • Back-door threats • Denial of service

16. Front-door threats • Arise when a user from outside the company finds a user password and logs on to the Network.

17. Front-door threats Solutions: • Separate Network resources accessed from and outside the LAN. • Control users accessing LAN from outside the LAN. • Set up a separate remote access account for remote users. • Set up user accounts to use dial-back. • Change password when employee with broad access resigns.

18. Back-door threats • Software or hardware bugs in the Network’s OS enabling an outsider to crack the Network’s security.

19. Back-door threats Solutions: • Host the company’s web site on an external server. • Implement a firewall router. • Review security settings for the web server. • Place web server for non-employees outside the firewall.

20. Denial of service • Attacks that deny service to the Network.

21. Denial of service Solutions: • Keep various Network software “current”. • Disallow Internet Control Message Protocol (ICMP) traffic service.

22. Denial of service • Demilitarized Zone (DMZ): The area between computers placed between the firewall an connection to an external Network.

23. VIRUSES AND OTHER MALICIOUS SOFTWARE

24. Virus • Program that spreads by infecting other files with a copy of itself. • Files infected by viruses include program files (.COM, .EXE, and .DLL).

25. Worm • Program that propagates by sending copies of itself to other computers. • Spreads by attaching to e-mails along with a message.

26. Trojan horse • Program that claims to do something interesting and performs malicious actions in the background.

27. Logic bomb • Malicious piece of programming code inserted into a normal program. • Can be timed to erase key files.

28. SUMMARY Internal security: • Account security • Account password security • File and directory permissions

29. Summary External security: • Front-door threats • Back-door threats • Denial of service

30. Summary Viruses and other malicious software: • Viruses • Worms • Trojan horses • Logic bombs