Comparison: Virus, Warm, Adware, Spyware, Trojan

We have all encountered terms like virus, warms, spyware etc many many times in the internet “jungle” without actually distinguishing between them. In this post I will try to define and compare all these malware threats that flow around the computer and internet worlds.

• Virus: A virus is a malware program that is loaded on your computer without your knowledge, with the intent of doing some damage to your system. It normally attaches itself to another program or data file in order to spread and reproduce itself in other areas of the computer without the knowledge of the user. Normally a virus enters your computer through a spam email which has attachments (pictures or files) or by downloading infected programs from malicious sites. A virus can damage files or cause your computer to behave strangely.
• Warm: Warms are memory-resident malware threats that can spread across networks by exploiting possible Vulnerabilities in the TCP/IP stack implementation of the OS and/or specific applications. They load themselves into the memory of a remote system and then execute themselves … all without ever being written to a disk. A warm therefore can live on its own and propagate by copying itself from one computer to another. Worms can harm a network, can consume tremendous bandwidth, and can shut a computer down.
• The difference between viruses and worms is that a virus cannot replicate itself like a worm, and it usually affects the computer it has invaded. A worm acts autonomously, and uses a computer network in order to multiply itself and to send copies of itself to other systems. A virus needs a user action (e.g download of infected file, run a program etc) in order to propagate and spread itself.
• Adware: An adware is certainly less threatening than a Warm or Virus. Typically, adware components install alongside a shareware or freeware application and bring targeted advertisements to your computer. These advertisements create revenue for the software developer. Adware displays web-based advertisements through pop-up windows or through annoying advertising banners. It can slow down your computer by consuming cpu, memory and bandwidth.
• Spyware: A spyware is closely related with adware, since it is usually transmitted also via freeware/shareware applications that we often download. As soon as it is downloaded it installs itself in your PC without your knowledge, and starts to monitor your internet activity. The monitored information is then transmitted to a third party, in most cases to companies which are interested in creating your personal profile. Later on, it will start sending you advertising or other data.
• Trojan: It is a program that appears to be working properly but actually causes damage in some form. It is called a Trojan because it can enter your computer through operations considered harmless, for example, through a game or even through a virus tracking program, and so it can trick the user by hiding the underlying activity. Like the ancient Trojan Horse, the Computer Trojan can secretly open ports on your Home Network. In general, Trojan horses cannot multiply themselves as warms do, but they rely on people to pass them around. The idea is to make the program look like it’s something harmless, like a screen saver or joke, so it gets sent around.

Bottom line is that you don’t want any of those little nasty codes on your computer. Fortunately there are several tools in the security “Arsenal” that can help you fight all these malware threats:

Antivirus Software

Antivirus software is the countermeasure program used to “inoculate” computer viruses. The software is installed on your PC and checks against viruses all files on your computer as well as files attached in incoming emails. If it finds viruses, it immediately informs you and, in most cases, it quarantines/cleans the infected files. The Antivirus can detect and clean both viruses and worms.

The Antivirus tool is a “must-have” software if you want to browse the Internet safely. The Three Best Antivirus Software available on the market today (which I am currently using on my personal computers) are the following:

1. Norton from Symantec
2. Kaspersky Anti-Virus Products
3. Trend Micro

Complete Security Suite

A complete security suite is a collection of tools for defending against malicious threats for your computer. The security suite usually includes antivirus, antispam, firewall, antispyware etc. An example of such a suite is The Norton 360 All-In-One Security

Although a security suite can help you prevent more types of malware compared with the standalone antivirus, the disadvantage of this software is that it takes more computer resources compared with a single antivirus solution.