Intruders are constantly trying to break into systems, snooping around, stealing software, and corrupting programs. Intruders are not particular about their targets.
Small systems are just as vulnerable as large ones.
Once your system has been compromised, it can no longer be trusted, so you can save yourself time and money by being prepared.
In this module, you will learn techniques to protect your system from unwanted intruders. By learning what intruders do when they break into your system, you will be able to better defend yourself against a break-in. You will also learn about known security problems and how to correct them. The techniques to determine whether or not your system has been compromised will also be discussed.

After completing this module, you should be able to:

1. Explain why it's important to protect your console
   
2. Describe security concerns related to network access
   
3. Explain how crackers get into a system
   
4. Describe what crackers do
   
5. List ways to detect attacks
   
6. Describe insecure remote login services
   
7. Describe secure remote login services
   
8. Control the root login process
   
9. Explain the use of the sudo command
   
10. Find modified and sticky files
    
11. Describe the cron facility
    
12. Describe RPM verification