COMPUTER VIRUS, WORM, MALWARE AND TROJAN HORSE

What is Computer Virus?

Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation.

A computer virus might corrupt or delete data on your computer, use your email program to spread itself to other computers, or even erase everything on your hard disk.

List of Known Viruses
http://en.wikipedia.org/wiki/List_of_computer_viruses

How Computer Virus Spread?

Computer viruses are often spread by attachments in email messages or instant messaging messages. That is why it is essential that you never open email attachments unless you know who it's from and you are expecting it. Viruses can be disguised as attachments of funny images, greeting cards, or audio and video files.

Computer viruses also spread through downloads on the Internet. They can be hidden in illicit software or other files or programs you might download.

What is Computer Worm?

A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers. Often, it uses a computer network to spread itself, relying on security failures on the target computer to access it. Unlike a computer virus, it does not need to attach itself to an existing program. Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.

Due to the copying nature of a worm and its capability to travel across networks the end result in most cases is that the worm consumes too much system memory (or network bandwidth), causing Web servers, network servers and individual computers to stop responding.

What is Computer Malware?

Malware is software, a computer program used to perform malicious actions. In fact, the term malware is a combination of the words malicious and software.

The end goal of most cyber criminals is to install malware on your computers or mobile devices. Once installed, these attackers can potentially gain total control of them. Many people have the misconception that malware is a problem only for Windows computers. While Windows is widely used, and thus a big target, malware can infect any computing device, including smartphones and tablets. In fact, the prevalence of malicious software infecting mobile devices is steadily growing. In addition, remember that everyone is a target, including you. The more computers and mobile devices cyber criminals infect, the more money they can make. These criminals usually do not care whom they infect, just as long as they infect as many people as possible.

What is Computer Trojan Horse?

A Computer Trojan horse, or Trojan, is a non-self-replicating type of malware program containing malicious code that, when executed, carries out actions determined by the nature of the Trojan, typically causing loss or theft of data, and possible system harm.

The Trojan Horse, at first glance will appear to be useful software but will actually do damage once installed or run on your computer.  Those on the receiving end of a Trojan Horse are usually tricked into opening them because they appear to be receiving legitimate software or files from a legitimate source.  When a Trojan is activated on your computer, the results can vary. Some Trojans are designed to be more annoying than malicious (like changing your desktop, adding silly active desktop icons) or they can cause serious damage by deleting files and destroying information on your system. Trojans are also known to create a backdoor on your computer that gives malicious users access to your system, possibly allowing confidential or personal information to be compromised. Unlike viruses and worms, Trojans do not reproduce by infecting other files nor do they self-replicate.

How to Protect yourself?

The best way to protect yourself is to ensure your devices are updated, have current anti-virus if possible and, ultimately, be on the alert for attacks.

Make sure your operating systems and applications are enabled to automatically install security updates.

Ultimately, the best way to defend against is keep your software up-to-date, install trusted anti-virus software from well-known vendors and be alert for anyone attempting to fool or trick you into infecting your own computer.