
The
Internet is a global system of interconnected computer networks that interchange data by packet switching using the standardized Internet Protocol Suite (TCP/IP).
Nowadays, most of the people rely on computer to store, disseminate and manage the important data. But the users must beware that their data may be stolen, loss, or misused by other people through
potential threats such as worms, computer viruses, trojan horse, security hacking, back doors and etc. Thus, the
computer security plays a significant role in protecting users’ data.
Internet security involves the protection of a computer's internet account and files from intrusion of an outside user.
Below are the types of
internet threats:
WORMS
A
computer worm is a self-replicating computer program. It uses a network to send copies of itself to other nodes (computers on the network) and it may do so without any user intervention. It can destroy data and programs as well as disrupt or even halt the operation of computer network.
TROJAN HORSE
It is a software program that appears to be benign but then does something other than expected.
Trojan Horse is not itself a virus because it does not replicate, but is often a way for viruses or other malicious code to be introduced into a computer system.
COMPUTER VIRUSES
A
computer virus is a rogue software program that attaches itself to other software programs or data files in order to be executed, usually without user permission or knowledge. Most computer viruses deliver a “pay-load”. The pay-load must be relatively benign, such as the instructions to display a message or image or it may be highly destructive. Viruses typically spread from computer to computer when human takes an action such as sending e-mail or copying an infected file.
BACKDOORS
A
backdoor is typically a password that known only to the attacker. It allows access to the system without having to go through any security. The backdoor may take the form of an installed program (e.g., Back Orifice), or could be a modification to an existing program or hardware device.
SECURITY HACKER
Hackers get the unauthorized access and use of networked computer systems. Illegal hackers frequently assault the internet and other networks to steal or damage data and programs. Hackers commit only electronic breaking and entering get access to a computer system, read some files, neither steal or damage anything.
There are various ways to prevent
internet threat:
=> Employ Strong Passwords
=>

Keep Software up to Date
=> Do not use piracy software
=>

Delete all the cookies in the computer to prevent track on the history/password.
=> Always scan your computer with Anti-virus
=> Turn on your firewall to prevent hacker
=>
Beware of Mail Attachments
In conclusion, risk facing by computer users is rising with the increasingly developed technology. Therefore, safeguards developed must be always up to date to enhance the defenses against online security threats.

References:
http://en.wikipedia.org/wiki/Internet
http://en.wikipedia.org/wiki/Computer_virus
http://en.wikipedia.org/wiki/Computer_worm
http://www.mailtrust.com/press-releases/2002/31