1. The client computer is usually insecure.
2. LANs are easy to eavesdrop on.
3. The intermediate networks comprising the Internet are public and open.
4. Web server may be insecure due to its operating system or lack of effective management.

Virtually every link in the connection between a client and a server is open to attack. Every time you use your credit card at a restaurant, gas station or mail-order house, you run the risk of having the card number stolen and misused.

Nowadays, Internet Security is something that has grown to be a main concern among society. It is important for users to aware that computer security plays a major role in protecting their data from loss, damage, and misuse. With the advancement of technology today, there are various online security systems or software could safeguard our data. However, there are also numerous of online threats that could attack our computer system, personal data and privacy anytime without our attention while we access the websites.

Some of the main online security threats that appear in the Internet are:
(1)Virus

Virus is a Malicious software that attaches itself to other software. For example, a patched software application. It’s a computer program that can replicate itself in some form and infect a computer without permission or knowledge of the user. Viruses can infect the boot portion of a secondary storage device and any type of file that can have a macro attached such as word processing and spreadsheet files. Besides that, virus also can easily spread by a user sending it over a network on the Internet or by carrying it on a removable medium such as floppy disk, CD, SB drive. For example, the May 2000 “I Love You” virus was a simple and small piece of code attached to e-mail which cause e-mail servers to overload and business to shut down email. It ever caused over $100million in US damages and over $1 billion in worldwide losses.

Worm is a program that copies itself repeatedly. The repeatedly copied files would use up the available space and slow down a computer operating speed. It is a software application designed to propagate through a network rather than through a single computer. When your computer is infecting of worm, computer will slow starting or slow running. It will also face unexpected or frequent system failures.

Trojan Horse is a software hidden in other software that is being distributed as a useful program. The Trojan horse may be a virus or a worm, or it may be surveillance software, such as a cookie, which communicates information back to a perpetrator. A Trojan horse will not execute unless the user runs the “covering” software in which it is hidden. Trojans will track into your computer and steal your personal information such as password of your e-banking account, email account and etc.

Spyware is any technology that aids in gathering information about a person or organization without their knowledge. On the Internet, spyware is programming that is put in someones computer to secretly gather information about the user and spread it to advertisers or other interested parties.

Denial of service attacks is another form of malicious code, are carefully crafted and executed. Denial of Service Attacks is not new, yet they are growing in sophistication. Traditional DOS attacks usually involve one computer attacking another, but the use of multiple computers in a highly organized attack is becoming increasingly common. Such attacks, known as Distributed Denial of Service attacks (DDOS), were witnessed in a number of large corporate computer shutdowns in 2000.

Those online security threats will try to steal your information from your computer through the Internet. It is very danger if our computer online without any Internet security system such as anti-virus. Therefore, safeguards developed must be always up to date to enhance the defenses against online security threat. There are five golden rules that we can do to prevent Internet threats which consists of:

1. Make sure you have the latest security updates & patches
2. Install anti-virus software
3. Use personal firewalls
4. Read our password advice
5. Use an anti-spyware program

By following these rules you will greatly increase your PCs protection when you use the Internet generally.

References: