Chapter 23. Securing Your Machines

IN THIS CHAPTER

• Understanding Computer Attacks

• Assessing Your Vulnerability

• Protecting Your Machine

• Configuring the SUSE Firewall

• Other Security Utilities to Consider

• What to Do if You've Been Hacked

• Keeping Up to Date on Linux Security Issues

It's an old story, but will remain true for the foreseeable future: The only method of keeping a computer 100% secure is to lock it in a room and never turn it on. The one thing computers do best is also the most dangerous thing about them they collect, store, and display information. Your job as system administrator is to ensure to the best of your ability that particular bits of information are displayed only to people and machines you want those bits displayed to.

With its permission-based file system, Unix and Linux make a good start on protecting your data from the bad guys. But the more connections your computer makes to other computers, first to a local area network, then to a wide area network, and finally to the Internet, the more chances your data have to be compromised.

In today's world of interconnected computers and "always-on" access to the Internet, the importance of maintaining a secure computer has never been greater. There may be some truly dangerous "cyber-terrorists" out there working at bringing down society as we know it, but these are not the people you have to protect your machine from. The ordinary computer user has to put up with the script kiddies (young folks who want to prove their alleged computer prowess by running prewritten programs that break into other people's systems), disgruntled employees, and fast-spreading viruses and worms. Unfortunately, that's more than enough to keep you busy for quite some time.

In earlier chapters, you've learned some basic skills for protecting your computer with permissions (Chapter 19, "Managing Users, Managing Security"), fighting viruses (Chapter 15, "Managing Email Servers"), and transferring files securely (Chapter 17, "Secure File Transfer"). In this chapter, the focus is on other tools to protect yourself and your information. You will also become prepared for the worst, having some idea of what to do when your carefully laid security strategy is somehow penetrated.