Computer Firewalls

A personal firewall is a software application, which filters traffic entering or leaving your computer.

When you're connected to the Internet, information is flowing to and from your PC in a near-constant stream through your PC's "ports". There are thousands of "ports" and they are like little gates that let information in and out.

Some of the information moving through the ports is obvious to you.

For example, when you:

Send and receive emails;

Access a website;

Fill in and submit a form on a website;

Download software

However, a lot of information flows to and from your PC without you knowing about it.

This can include:

Your copy of Windows talking to the Microsoft website to check for security updates;

Software applications talking to their own companies' websites to check for new versions;

Anti-virus software checking for the latest virus updates.

Most of this invisible information flow is good. However, some of it poses a grave threat to your PC and your privacy.

Your email isn't the only way bad things can get into your computer. They can come in through your PC's open ports without you even knowing about them. The "Blaster" worm of August 2003 was the most widespread example of this. In case you don't remember, that was the one that caused your PC to shut down about a minute after you'd started it up!

If you leave your PC's ports open and don't monitor them, you're at extreme risk of the following nasties:

VIRUSES: Programs or pieces of code that "infect" one or more of the programs on your PC. Basically, your programs "get sick" and start performing in weird ways, which sometimes can lead to a system crash.

WORMS: Malicious programs that propagate over a network, reproducing as they go. Worms cause the same effects as viruses but they are more dangerous since they spread by themselves.

PORT SCANNING: Hackers scan the open ports on your PC to figure out if they are open or exist at all. If your computer reports an open port, a hacker can send a worm and virus to it. They can even use an open port to take control of your PC.

COOKIES: Small data files placed on your PC by a website that you've visited. A cookie can store your personal information after you enter it online. For example, if you type in your credit card number, a cookie might store it till you come back next time. This is not a bad idea - most shopping sites use cookies completely legitimately so you don't need to keep entering your personal details. But problems can occur when other people decide to use your credit card too!

TROJANS: Programs that appear legitimate but do something illicit when run. Just like the wooden horse the Greeks gave Troy as a "gift", users mistake the Trojan for a useful or interesting program that they choose to download. Once installed and run, Trojans can secretly open remote access channels to hackers, relay passwords and credit card data or destroy user files. It's similar to a virus but generally does not replicate itself.

DENIAL OF SERVICE (DOS) ATTACKS: This kind of attack happens when a hacker finds a responding port on your PC and sends a huge amount of data to it. The port is just unable to accept all of the data, the system resources exhaust, and the system crashes and denies service.

Software secretly placed on your PC that gather information about you (such as your surfing habits, what other software you have on your PC, etc.) without your knowledge or consent. Spyware is mostly used by on-line or software companies for marketing purposes.

So how does a firewall help to stop all of these bad things from happening?

As I said at the start, a firewall controls communications to and from your PC. It permits or denies communications based on a Security Policy.

According to the security policy you set for it, a firewall can...

Make your PC invisible on the Internet. Your ports don't just appear closed;

they don't even appear at all. This is very good!

Automatically block suspicious incoming traffic;

Alert you every time a program on your PC tries to send information to another computer.

This stops Spyware and Trojans from sending hackers your confidential information,

such as credit card details and passwords;

 Do a lot more things too, but these are the most basic and important functions it carries out.

So in short, if you don't have a firewall installed, then as soon as you connect to the Web (before you even start your browser or e-mail client) you are open to attack - because some or all of your ports are open and unmonitored. A firewall is especially important if you have a high-speed Internet connection. Hackers love to take over broadband machines because then they can use them to spread Spam even faster!

Now you're probably wondering where to get one of these firewalls, aren't you?

There are some good firewalls around, but the one that we all use here in the office is Outpost Pro, made by Agnitum. We recommend it to our customers - it's a great product. It's easy to use if you're a beginner and if you're more advanced, it gives you lots of different options. Check out the Outpost website. We've set up a link to it from the Firetrust site:

http://www.firetrust.com/firewall/

What is Phishing on Computers?

Phishing is a high-tech scam. The "phisher" uses spam or pop-up messages to trick you into giving

out sensitive information like your passwords, credit card numbers, bank account information,

or Social Security number.

Funnily enough, phishing is nothing new.

It used to be known simply as identity theft and the scammers usually did it over the telephone.

The scammer would call you up and pretend to be someone from the bank asking you to confirm

your account information, credit card numbers, PIN numbers, or passwords.

Obviously the scammer was limited by the amount of time it took to ring each person,

so identity theft never really took off until the advent of email Spam and websites, which meant

 identity theft has become much more profitable and therefore widespread. Unfortunately,

it is now an everyday occurrence.

Here's how phishing works:

The scammer uses Spam to send the phishing messages.

You'll receive an email or pop-up message that looks like it's from a business or organization

that you deal with – e.g.

Your Internet service provider (ISP), AOL, MSN, BT Yahoo, and Earthlink

Your bank e.g. Lloyds TSB, Barclay, etc

Your online payment service e.g. PayPal

A government agency

The message usually says that you need to “update” or “validate” your account information,

and there's usually a threat they will do something bad if you don’t respond within a short period

of time, like close your account or charge you a fine.

So, you click on the link in the email and it takes you to a website that looks just like the legitimate organization’s site, but it's a carefully constructed fake. This fake site tricks you into entering

your personal information. Using this information, the scammer can then steal your identity

and run up bills or commit crimes in your name.

Phishing is becoming big business. In September 2003, the US Federal Trade Commission

reported "9.9 million U.S. residents were victims of identify theft during the previous year, costing businesses and financial institutions $48 billion and consumers $5 billion in out-of-pocket expenses."

Phew, that's a lot of people and a lot of money!

The biggest phishing scam in history occurred in November 2003,

when a PayPal phishing message was sent to millions of people irrespective of whether

they had a PayPal account or not. The scammers knew that there would be enough people

with PayPal accounts to make it worthwhile for them.

So you probably want to know how to avoid phishing scams.

1.  Change your attitude and behaviour towards suspicious emails and pop-up messages. Become more vigilant. If in doubt, delete it. That's why MailWasher has a 'Delete' box!

Check carefully the URLs (links to websites) within the email by using the preview pane in MailWasher. They might be links to fake websites.

Even if it is from an institution that you use, like your bank or your ISP, telephone them to confirm that they did indeed send out a message. If the message asks you to enter confidential information about yourself, such as your password or PIN number, it is almost certainly a scam. Institutions like these almost never ask for such information over the Internet.

Don't give your account details to anyone without contacting them first by telephone and making sure the email is legitimate.

2.  Install security software. Nowadays, you need a firewall and an antivirus as much as you need locks on your doors at home. You wouldn't go out leaving all your doors open, would you?

Some phishing emails contain software that can track your activities on the Internet without you knowing about it, so make sure you're screening your incoming mail with up-to-date antivirus software.

3.  Finally, make sure you keep up-to-date with Microsoft's patches. The latest research shows that an unpatched Windows XP computer has a life expectancy of less than 20 minutes before it is compromised. That's less time than it takes to download the patches!

So check out Microsoft's Update page to make sure you're up-to-date.

By kind permission of Nick Bolton Firetrust http://www.firetrust.com,

What is Spyware?

Spyware refers to a category of programs that illegally monitor your computer activity, often capturing and transmitting your personal information without your knowledge. In the process, they often cause your computer to become slow and unstable, and cause problems when you connect to the Internet.

Is it the same as Adware?

Adware is legally installed software that tracks your online behaviour while you surf the Web. Some adware programs transmit this information to online advertisers, who can then target you with advertising based on your surfing habits.

Adware also includes cookies, which are small programs placed on your computer while you visit shopping sites. Cookies are normally harmless. Without them, e-commerce would be a tiring exercise in filling out forms every time you visited each site. If in doubt, read a site's privacy policy before you enter personally identifiable information at their web site.

What sort of personal information can Spyware and adware send to other people?

Adware can send a record of the websites that you have visited.

Spyware is different. Some kinds of Spyware called keyloggers can record all of your keystrokes and transmit them without your knowledge. This means that all of your passwords and credit card details can be compromised.

What harm can these programs cause?

Apart from the disastrous effects of identity theft, Spyware also causes numerous side effects.

If you've noticed that your PC has become slow and unreliable, has trouble connecting and acts strangely when you're surfing the Internet, then it's likely you've got Spyware on your system.

The slowness and unreliability comes from the Spyware consuming your system's memory and processing power at the expense of the programs you actually want to run.

The strange behaviour when you're online can include your home page changing and your browser redirecting you to sites that you've never heard of, let alone wanted to visit. Often these are pornography, financial services, or pharmaceutical sites. In other words, the sort of things those spammers try to sell you!

Even more alarming is the emergence of stealth dialers. These are programs that, once placed on your machine, proceed to dial up premium-rate international phone numbers. You don't know they're there until you receive a gigantic, inexplicable phone bill at the end of the month!

In a recent survey by AOL, 80% of the users had some form of Spyware or adware on their machines. Of these, 90% did not know about the infection and, even worse, didn't even know what Spyware was!

For these reasons, Spyware has replaced viruses as the number one security threat to PCs.

How can I stop Spyware from getting onto my PC?

Popular free applications like music-sharing programs and even instant messaging software can come with Spyware or adware bundled. If in doubt, don't install these programs.

Keep your web browser up-to-date with Microsoft's security patches by going to Microsoft's Update Page:

http://windowsupdate.microsoft.com/

And make sure you NEVER click on links in Spam messages, no matter how tempting it is! These links will often open sites that download Spyware and hijack your browser.

How can I stop Spyware from stealing my personal information?

You should install a personal firewall to stop Spyware "phoning home" in the event that it does get onto your system. We recommend Outpost Pro but there are some good free firewalls around too.

How can I detect and remove Spyware from my PC?

Download a Spyware detection and removal tool. I recommend that you select from the following list of products. They seem to have different strengths so use more than one of them.

Spyware Doctor

Spybot Search and Destroy

Ad-Aware

PestPatrol

Spy Sweeper

Be very wary about downloading other Spyware removal tools, because many 'anti-Spyware products' actually install Spyware of their own on your computer!

Further reading

For further reading, visit these excellent anti-Spyware resource sites:

http://www.io.com/~cwagner/spyware/

http://www.freespywareremoval.info/

http://www.free-spyware-adware-removal.net/index.html

By kind permission of Nick Bolton of Firetrust www.firetrust.com