By Boris Loza, PhD, CISSP
Today, even your grandmother probably knows who hackers are. But do you know who hackers really are and how they work? In this school we will try to answer some of your questions and show you how hackers work and how, step-by-step, to defend against them. I will even teach you some "harmless" ethical hacker's tips and tricks (remember that hacking is illegal and is considered as a criminal action!). You will also learn more about hackers and decide by yourself whether hackers are "real geniuses" (as some people believe) or not.
Initially the word "hacker" was used to describe a person who lives and breathes computers, who knows all about computers, who can get a computer to do anything... But nowadays the media has been referring to computer criminals as "hackers". The "old fashion", "real" hackers, refer to computer criminals (who cause harm to computers, release viruses, and so on...) as "crackers". Real hackers (computer gurus) are upset with the misuse of the term "hacker". In their own words:
And most crackers are not geniuses at all! For example, the "biggest and famous hacker of our time", Kevin Mitnik, according to Carolyn Meinel the creator of the "Happy Hacker" web site, "was famous for begging people to compile exploit programs for him. He never learned how to program, he just learned to beg other people for point and click exploit programs"! But because "hacker" today is a common name for computer criminals we will use "hacker" and "cracker" interchangeably in these lessons. Next time we will talk about different categories of crackers - their hierarchy.
We believe that if you are more aware of how computer criminals work you, on the one hand, won't be afraid of hackers/crackers and, on the other hand, will ensure that any security loopholes are fixed even before the cracker strikes.
Today we will show you how you can protect your home computer without too much "hassel". Today we will set up a personal firewall.
A firewall is an application that protects your computer from hackers/crackers on the network. Firewalls look for rogue patterns in network traffic to prevent intrusions. When you connect to the Internet your computer is exposed to any cracker who may tray to break into it.
There are a number of commercial firewall utilities avaliable that you can use to protect your system, such as Norton Personal Firewall, McAfee Firewall, Nexland and NetworkICE's BlackICE Defender. However, there are also a number of freeware tools ("free" doesn't mean "cheaply made"!) that you can download from the Internet including:
In this lesson we will install and configure Sygate Personal Firewall. By using this application you can not only protect your personal computer from malicious Internet users, but also restrict your kids' access to the Internet by specific times (e.g. stop Internet usage after 9.00 p.m.) and/or specific applications (e.g. stop using MSN, ICQ, KaZaA etc..)! You can install it on Windows 95/98/ME/NT/2000/XP. It is free for personal use but requires registration if you want to access on-line support.
Step 1. Download and install Sygate Personall Firewall from http://soho.sygate.com/free/default.php#spf (Note, that Firewall PRO is for commercial use only and Personal Firewall is free). Restart your computer when prompted.
Step 2. Once you've restarted your PC, the program will begin protecting your computer. Fire your Internet browser or email application and you will see something like this:
Or this:
You'll want to allow these applications, so tick the "Remember my answer box" and then click "Yes". Many other programs access the Net when you launch them to search for update versions or to download the latest welcome page. If you want to block these programs, launch them and select "Remember my answer" and "No" from the Sygate dialog box.
Step 3. Crackers can't access your system unless they can identify an open port (we will discuss ports in one of the next lessons) on your PC. As well as blocking any attempts at port scanning your PC, the firewall also keeps a log of any such scans.
Double-click on the small firewall icon in the low-right corner of your desktop:
This will bring on the firewall interface:
Click Logs/Security Logs to view a list of transgressions along with the IP addresses of the offenders:
Step 4. You can also block all connections when you're not at your PC or to prevent children accessing the Internet after bedtime. You can also restrict or allow access to the Net by specific applications at specific times: go to "Tools/Advanced Rules" and click the "Add" button. Enter a rule description and go to the "Scheduling" tab. Click "Enable" and select the period each day when you won't be using your PC. Click "OK" and "OK" again to apply the rule:
Step 5. To stop your kids from accessing the Net, create a rule and hide your firewall (I also recommend setting up a password. It is hard to hide something from today's kids!). Go to "Tools/Options" and select "Hide Sygate Personal Firewall System Tray Icon":
Also check "Ask password while exiting icon" to prevent kids from disabling the firewall.
By setting the password you will make your firewall more secure, because some Trojans (we will discuss Trojans on the next lesson) and viruses can disable antiviral and firewall programs!
Should you wish to change or monitor your firewall settings, you'll need to access the program through the "Start" menu and enter your password.
Step 6. Now that you've got your firewall up and running just as you like it, it's probably an ideal time to test its capabilities. You can do this by clicking the "Test" button and using the tools on the Sygate Web site. A more impartial alternative can be found at www.blackcode.com/scan:
Or https://grc.com/x/ne.dll?bh0bkyd2, the Shields Up Web site. Click on "Test My Shields!" and "Test My Ports!" buttons:
Happy Internet surfing! I will see you at my next lesson.
Regards,
Boris Loza