No matter why you have a computer at home or what you do with it at the office, virus prevention should be of utmost importance to you in the battle to save your hardware and data from viruses. In order to better understand the odds, one has to have an understanding of different aspects of computer virus prevention and how to protect your computer from viruses. Regardless of the software you choose for your antivirus protection, it is only as good as you keep it.

In this way, antivirus software is as young children would be; you feed them, send them to school and set structure for them. The feeding is metaphorically performed by acquiring updates to the anti-virus program, (called virus definitions), you send them to school by going to the vendor and getting updates to the program, and lastly you give them structure by going into the program and telling the application when to eat, when to go to school and when to watch TV (effectively when to scan, when to update itself, and where to search for viruses).

Always remember that no anti-virus software is 100% all the time, with that said here is my golden rule. The golden rule in fighting viruses is to back up your critical files, like the latest newsletter from San Diego PC Help, pictures, music, etc. I will go into more detail about performing backups to your critical files in an upcoming newsletter. Please feel free to contact your local professionals at San Diego PC Help if you think you have an issue and need help now. OK, so here let’s look at the different types of viruses that we have today.

Types of Viruses – What is a Virus?
A virus is basically malicious computer code that has the ability to cause havoc in a number of ways; it works by destroying the data and programs on affected systems. It can log keystrokes in order to gain sensitive information such as passwords, and it can remove personal information stored on a computer. Not all computer viruses behave, replicate, or infect the same way. There are several different categories of viruses and malware. Below I list and discuss some of the most common types of computer viruses.

Trojan Horse:
A Trojan horse program has the appearance of having a useful and desired function. While it may advertise its activity after launching, this information is not apparent to the user beforehand. Secretly the program performs other, undesired functions. A Trojan Horse neither replicates nor copies itself, but causes damage or compromises the security of the computer. A Trojan Horse must be sent by someone or carried by another program and may arrive in the form of a joke program or software of some sort. The malicious functionality of a Trojan Horse may be anything undesirable for a computer user, including data destruction or compromising a system by providing a means for another computer to gain access, thus bypassing normal access controls.

Worms:
A worm is a program that makes and facilitates the distribution of copies of itself; for example, from one disk drive to another, or by copying itself using email or another transport mechanism. The worm may do damage and compromise the security of the computer. It may arrive via exploitation of system vulnerability or by clicking on an infected e-mail.

Bootsector Virus:
A virus which attaches itself to the first part of the hard disk that is read by the computer upon boot up; these are typically spread by removable media.

Macro Virus:
Macro viruses are viruses that use another application's macro programming language to distribute themselves. They infect documents such as MS Word, Excel, or emails, and are typically spread to other similar documents.

Memory-Resident Viruses:
Memory Resident Viruses reside in a computers volatile memory (RAM). They are initiated from a virus which runs on the computer and they stay in memory after its initiating program closes.

Rootkit Virus:
A root kit virus is an undetectable virus which attempts to allow someone to gain control of a computer system. The term root kit comes from the Linux administrator root user. These viruses are usually installed by Trojans and are normally disguised as operating system files.

Polymorphic Viruses:
A polymorphic virus not only replicates by creating multiple copies of itself, but it also changes its digital signature every time it replicates. This makes it difficult for less sophisticated antivirus software to detect them.

Logic Bomb/Time Bomb Viruses:
These are viruses which are programmed to initiate at a specific date or when a specific event occurs. Some examples are a virus which deletes your photos on Halloween, or a virus which deletes a database table if a certain employee gets fired.

Sometimes I wonder if the virus protection companies are putting out these viruses just to keep you on edge about them. I know this is not a true statement (well I certainly hope this is not a true statement, anyway). We hope you’ve enjoyed this brief but insightful look into the world of malicious software. More news is to come, especially on the topic of backing up critical files and steps to take before infection. If you find yourself in the position where one of your computers is infected and you are unable to use it any further, remember that San Diego PC Help is here to give advice and help remove such infections. Stay tuned for more news.