An attacker or malware only requires three elements to exploit the vulnerability:

1. A flaw in the system.
2. An attacker’s access to the flaw.
3. The attacker’s ability to exploit the flaw.

In a recent experiment conducted in the United States, several new Windows XP computers were connected to the Internet using a DSL connection. They had the latest operating system patches but no anti-virus and no firewall. They recorded an average of 300 security intrusions per hour at the end of the first day!

Some of the common yet dangerous computer and network vulnerabilities include:

• Unsupported or unpatched operating systems. Windows 95, 98 and NT Networks are no longer supported by Microsoft. XP Home or Windows Me are never appropriate for office usage. Only Windows XP Professional or Vista Business is recommended for office usage. Make sure that your operating system has the latest service pack updates installed.

• Even though anti-virus software is installed on 95% of the computers, in 90% they are not configured properly. Then what’s the point of having anti-virus SW? Make sure that you download and install periodic updates from the Internet.

• Never go for free or cracked anti-virus software to save a few bucks and expose your computer to serious threats.  Free AV is only recommended for light computer use.

• If you are an Internet junkie that engages in risqué habits (i.e. pornography, black-market, and underground sites) then it is imperative that you install a hardware firewall as opposed to just a software firewall.

• Most of the time it is we who expose our computer or network to vulnerabilities by downloading and installing peer-to-peer file sharing software like Kazaa, Limewire, Morpheus etc.

• Downloading and installing screensavers and playing online games can also be threatening to your computer due to patchy software with vulnerable holes.

• Installing Freeware or software that is free. We do it because…well…they are free! But they can be also dangerous, you just don’t know where it came from or if it is being properly maintained and updated.

• Not backing up your data is a disaster waiting to happen.  All hard drives will eventually fail.  So, unless you are backing up your data regularly, be prepared for it to vanish.  There are companies that can recover your data but they are expensive!

Also, power spikes and outages are also extremely dangerous for your computer and network. So using a UPS will prevent this, and prevent disconnections from the net.

If you have a wireless network, you should be even more careful with your network. It is extremely easy to sneak up on wireless networks and go undetected. And since a wireless connection is popular nowadays, you probably have even noticed, while you are checking your mails sitting in your bedroom; your neighbors network! Some ways to protect your WiFi connection are:

• Use preferred encryption methods in this order:

1. WPA2
2. WPA (been cracked)
3. WEP (been cracked). Use WPA and WEP if you have no other choice.

• Change your SSID code every two weeks and keep it something obscure that is hard to guess.
• Keep the ‘broadcast SSID’ option in your WiFi turned ‘off’.
• Turn off your WiFi when you are not using it and use an alternative.
• Disable DHCP on the entire network.

Install a web filter. This device controls access to certain websites and content. If you have children in the house, you might want to keep this turned on. There are some open source web filters available on the web like:

B Gone

K9 Web Protection

Privoxy

Parental Filter

Install a spam filter, desktop firewall software, and antivirus and make sure that you update and maintain these regularly.

Installing encryption software will prevent prying eyes from gaining access to your personal data. Apple has harddrive encryption functionality built-in. It is called FileVault. However, it does not work with Time Machine.?

There are also various password management software that let you create and remember extremely complex passwords. A useful tip: never use a single password for everything. Never use the password you use for your emails and bank accounts on open source software.

It is also important to install a back-up and recovery system. So that if, unfortunately, your computer crashes, you will still have all the important data and files intact.  These few tips will go a long way toward maintaining a secure home network.  The rest involves staying up to date on the latest security threats and acting accordingly.

The very first computer worm was unleashed accidentally in 1988 by Robert Tappan Morris. Another well-known computer worms was the SQL Slammer Worm of 2003, which owing to vulnerability in the Microsoft SQL, spread itself across the Internet.

The Blaster Worm used the Microsoft DCOM RPC, which is a technology for communication among software components across networked computers, in order to spread itself.

Some worms like the 1999 Melissa Worm, the 2003 Sobig Worms and the 2004 Mydoom worms used email to spread. These worms had some qualities of Trojans whereby they attached themselves to an email attachment and prompted the end user to open the attachment thereby causing infection to the computer.

To prevent computer worms infection and spreading:
• Keep the operated system, hardware, and software patched and up to date.
• Never open unsolicited email attachments because there could be a Trojan-like worm inside. The worms in attachments are not just limited to .exe files but can also be contained in Word and Excel sheets.

Worms can also spread through Instant Messaging services. There also may be links, which lead to malicious sites. Once clicked, the worm may be transferred through the network to your computer.

However worms are not always malicious. There have been ‘good’ worms as well! For example, the Nachi family of worms had been created to perform useful functions like download and install patches from Microsoft’s website to fix vulnerabilities in the host system.

However, the most important protection against this especially dangerous type of malware is caution and good antivirus software.

Here are some easy ways to spot if your computer is infected by malware. For your convenience, we will divide the symptoms in two broad categories: Symptoms found during surfing the net and symptoms found while generally working on the computer.

While Internet browsing, your computer may be infected if:

• Excessive pop-ups that keep popping up no matter whatever you are browsing. Also if these pop-ups are X-rated, you can be sure that something is not right!
• You are greeted with a homepage that you don’t recognize or don’t remember having set it. If repeated attempts at changing the settings fail, you should definitely be concerned.
• Your browser crashes unexpectedly or presents error messages mentioning unusual file names.
• Browsing speed is slow. But in certain countries owing to a difference in bandwidth, browsing speed maybe naturally slow. What I mean is, if your browsing speed is slower than usual and if you find pages taking an eternity to open, you should definitely scan your computer for infections.
• Your bookmarks or your favorites have changed without your knowledge.
• The search engine preferences have been changed without your knowledge.

While general use, your computer may be infected if:

• Your computer becomes slow, programs do not respond to commands and machine hangs.
• You notice unfamiliar icons and shortcuts on your desktop which weren’t there before. Also if there are significant changes in your desktop appearance, color schemes wallpaper, font size etc.
• Your computer shuts down unexpectedly.
• Your taskbar vanishes.
• You notice unfamiliar message boxes.
• While shutting down, your machine notifies you that there are ‘other users’ connected to the same network.
• Your machine freezes without warning.

We are cognizant of the fact that each computer user will have their own preferences when it comes to choosing the antivirus software that is best suited for them. While one user may want fast scanning another may require a built-in firewall.

Without getting into a pointed row, we want to give you our suggestions for the top free antivirus software available. These three were chosen because of their popularity and our own personal experiences. We will not try to rank them but instead randomly present them along with their respective benefits and faults.
So, when it comes to the best FREE antivirus software, the A’s win hands down. They are, in no particular order:

• Avast Home Edition Anti-Virus
• Avira Free Personal Anti-Virus
• AVG Anti-virus Free Edition

Lets begin with Avast. The user interface is relatively simple, functional, and customizable with loads of features. It has an ‘active protection’ feature that monitors seven different ways a virus could enter your computer which includes Internet browsing, checking emails, file sharing and so on.

Avast lets you scan the computer upon boot up. However, if you choose to scan on start up, the booting process may take a longer than usual.

Avira lacks the built-in anti-spyware detection system that Avast boasts, but it has a higher virus detection rate than Avast. The anti-spyware is available only with the paid version of Avira.

AVG is the most popular free antivirus software on the market. Its interface is polished and easy to use.

Although AVG detects viruses as well as spyware, its detection rate is slightly slower than Avast.

A lot of functionality is left out of the free version of AVG and is available only in the paid version. Despite this, AVG still provides good overall basic protection for your machine.  In the end you will have to choose for yourself depending on your needs.  The price is right so you can give all three a try.

The links where you can pick them up are below.

Avira

Avast

AVG

What are your suggestions for free antivirus software?