Keeping out the Hackers

Given the recent rash of viruses grabbing headlines it makes sense that we turn our attention to security. Over the next few issues we'll examine this in detail but for now let's get an overview of what we can do to secure our systems.

You may feel you're not a target of hackers because you're small enough to slip under their radar. Don't be so sure. There doesn't have to be a financial motive. While it's to be expected that banks, megacorporations, and government agencies are the preferred targets of experienced hackers, many inexperienced hackers get started attacking small businesses and home computers that are less well protected. Once inside they may do little more than snoop around or commit minor acts of senseless vandalism, deleting or altering files. For many, just the thrill of getting in where they're not supposed to be is enough.

However -- and this is more serious -- they may use your system as a launching pad for an attack on another, larger system. That way, if that next target traces the intrusion, it will lead back to you, not to the hacker.

Furthermore, attacks come in various forms. Some are not designed to infiltrate your system, merely to shut it down. Denial of service attacks (DoS) seek to so overload a system with rogue connections that it can't respond to legitimate requests.

So how do you protect yourself?

Firewalls

A firewall acts as a barrier between your local area network (LAN) and the wide area network (WAN) of the Internet. In its simplest form it only allows access to data you specifically request, using a web browser or email client.

If you're running your own server and you wish to allow outside people to reach it, the firewall can be configured to grant that access according to specific rules. You can allow access from only certain internet addresses, to only certain services on your server, or at only certain times.

Firewalls generally take one of two forms: either a dedicated hardware device like a D-Link (http://www.dlink.com) or LinkSys (http://www.linksys.com) router, or a piece of software running on your computer, like NetBarrier from Intego (http://www.intego.com) or Norton Internet Security from Symantec (http://www.symantec.com). The advantage of the hardware firewall is that it will protect your whole network; a software firewall will only protect the machine it's running on (unless you configure that computer as a router itself.) However, software firewalls are more easily upgraded to cope with new attacks.

Antivirus

Viruses, worms, and trojans gain the most publicity, which is often exactly what their creators want. We'll go into details about these, how they work, and the differences among them in a future issue. The important thing to understand now is that a good antivirus scanner is a necessity if you wish to keep your computer system safe and reliable. Fortunately there are some good tools available. Two of the most popular are from Symantec (http://www.symantec.com) and McAfee (http://www.mcafee.com).

Viruses are identified by their signatures. Good antivirus vendors release signature updates on a regular basis, at least monthly, but sometimes weekly or even daily if new virus threats are discovered. Choose one from a vendor that provides regular updates to cope with new and variant viruses. If the utility can automatically download its own updates from the vendor's web site, even better. You many have to pay a subscription fee for this service but it's well worth it.

Closely related to viruses is spyware. These programs often masquerade as file-sharing utilities but their real function is to gather your personal information - credit card numbers, passwords - and forward it to some nefarious individual. Ad-Aware (http://www.lavasoftusa.com) and Spybot (http://www.spybot.info) are two tools that will detect and remove spyware but there are many others.

Encryption

Do you send confidential information through email or FTP? Would it bother you to know someone might be reading your mail? If so, consider encrypting it with PGP (Pretty Good Privacy.) PGP (http://www.pgp.com) is free for personal use and reasonably priced for commercial use. It employs public and private keys. (You encrypt a message or a file with someone's public key and only that person can decrypt it with their private key.) While no password protection is literally unbreakable, PGP comes pretty close.

Wireless

Do you have a wireless network? They're becoming increasingly common as the hardware comes down in price, the bandwidth increases, and the configuration becomes easier. At the same time, wireless networks present their own security challenges.

In Toronto recently, an individual was caught downloading child pornography while parked outside homes and businesses with unsecured wireless networks. If the authorities had tracked those downloads they'd be led to those innocent -- but careless -- bystanders. Even if no charges were laid it could prove embarrassing and costly.

Read the documentation that comes with your wireless equipment and follow the instructions for setting passwords and enabling security.

Prying Eyes

Don't forget the physical security of your systems. A clerk at a travel agency carelessly left her computer on over night with the monitor visible from outside. Anyone walking by could read the itinerary on the screen and know when a particular family was going to be out of the country, leaving their home a ripe target for thieves.

Do you have a janitorial staff that comes in after hours? Would you mind if they looked through your files? Lock your computers with a password protected screen saver or, better still, shut them off and make sure they require login passwords when you start them up. You'll be more secure and you'll save electricity too.

Patches

We hear a lot about the security holes in Microsoft Windows and it's associated applications like Outlook and Internet Explorer, but the fact is, every operating system, every piece of software may have security holes and bugs. Vendors are beginning to recognize their responsibility to keep their software up-to-date with patches that cover any holes found. Microsoft, Apple, and many Linux distributors now provide automatic update services. Learn how to use them to keep your system patched with the latest security fixes.

Follow these simple precautions at all times:

• Don't open email attachments from people you don't know.
• Don't download pirated software or music files. (It's not only illegal; these files are often infected with viruses.
• Keep your firewall, antivirus, operating system, and other software up-to-date.
• Secure your wireless network with passwords.
• Use encryption when sending confidential material.
• Shut down your computers at night or lock them with a password-protected screensaver.

In a perfect world we could trust everyone. There'd be no reason for locks or security systems for our homes or our cars ... or our computers. But we're not there yet. In the meantime, play safe.