A virus is a computer program that can replicate itself and spread from one computer to another.
If you don't get rid of the virus, there is a strong likelihood that eventually you'll pass it on to someone else and if that is a supplier or customer; this may cost you a lot of money in lost business as it will reflect on you and your business.
At least 99% of viruses are memory resident, so there is the possibility of incompatibilities between the virus and other programs you are running; including your main business software!
In addition, even though the virus might be well known you will remain nervous that the virus does more than has been documented or that you have a different version of the virus.
In other words you must get rid of the virus.
A computer virus is a small software program that spreads from one computer to another and interferes with computer operation. A computer virus might corrupt or delete data on a computer, use an email program to spread the virus to other computers, or even delete everything on the hard disk.
Computer viruses are frequently spread by attachments in email messages or by instant messaging messages. Therefore, you must never open an email attachment unless you know who sent the message or you are expecting the email attachment. 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 pirated software or in other files or programs that you might download.
The war on computer viruses has led to an arms race between the designers of antivirus software and the designers of viruses (you didn't think viruses just created themselves did you?). Some years ago, virus designers responded to ever more successful antivirus software by creating the descendents of viruses, worms, which did not infect files but rather installed themselves directly on the hard drive, making them harder to detect.
The arms race has since led to many distinct types of what is now called malware, a neologism meaning bad (as in malignant rather than shoddy) software. According to Wikipedia, these eleven types of malware are:
- Key Logger
- URL injection
As you can see, makers of antivirus software have their work cut out for them if they're going to keep every instance of malware off your system. As a result, antivirus software makers have often had to pick their battles. Adware, whose makers often claim they are doing nothing illegal or even questionable, often gets treated more lightly.
Even when antivirus software makers do come out with a product that fights all twelve or so kinds of malware, responding to each new instance of malware to come on the market isn't easy. First the malware has to be identified, which means someone's computer, and probably tens of thousands of computers, will be infected first. Then, the malware has to be dissected. Then a removal program and a filter must both be written. Then the removal program and filter must be tested to make sure they work, and that they don't interfere with any other functions of the antivirus software or the computer itself. When a fix for the virus is out, it then has to be loaded into an antivirus software update and transmitted to every single computer worldwide that has the antivirus software installed.
The speed with which antivirus software makers are able to deliver updates for newly discovered malware would impress even Santa Claus. Yet there's still a crucial window of one to a few days between when the new malware has reached a critical mass of thousands of computers, and when the update is released. If your antivirus software is not set to check for updates automatically every hour or so, that window opens even wider.
Practically speaking, then, you're better off having more than one line of defense against malware. Even if two different anti-malware programs utilize the exact same database, there might be a crucial difference in the speed of getting updates. It makes sense to back up your antivirus software with anti-spyware software. When you consider that dedicated anti-spyware software developers make protection against the non-virus forms of malware their stock-in-trade, you can see why anti-spyware software is so essential. In fact, you should strongly consider having two anti-spyware programs running on your computer at all times, since the gap in updates between two anti-spyware programs can be even longer than for two antivirus programs.
After all, with a dozen kinds of malware out there, shouldn't you at least have two pieces of software to fight them?
The most common viruses are
- Encrypted Viruses – The encrypted virus is probably the most difficult kind of bug to detect and the most difficult to stop. You may accidentally have downloaded one of these bugs and before you know it, your entire computer can be infected. Many top virus protection programs miss encrypted viruses because these bugs use a different form of encryption every time. When the bug wants to run wild, it decrypts itself. In most cases, your virus protection can then identify it and stop it.
- Secret Viruses – These types of viruses will make changes to files on your computer, or completely replace files, but then try to trick your computer and your anti virus program into thinking that the originals are being used. Most advanced virus protection programs can stop these common computer viruses dead in their tracks.
- Time Delay Viruses – These types of viruses take a much slower, more disciplined path towards ruining your computer. Instead of instantly trying to take over your computer the moment you download them, they will wait and slowly infect files bit by bit. You may not have been online for days but then suddenly find yourself with an infection. These common computer viruses are the reason why you should run your virus protection every few days, just in case.
- The Anti-Virus Virus – Believe it or not, there are viruses out there that do nothing more than attack your pre-installed anti virus program in hopes of disabling it so other viruses can then be downloaded. This is why many people have a virus protection program as well as a separate anti-spyware or anti-malware program on their computer.
- The Multi-Headed Virus – This is one of the most nefarious bugs on the whole Internet. Not only are there parts of this virus that will attach themselves to .exe files on your computer, but it will also affect your computer’s start up so that you begin running the virus every time you turn your computer on automatically.
- The Misdirection Virus – This type of virus is downright scary. It has a built in subprogram that is made to give false readings to your virus protection software. You think you have a bug in one directory, when, in fact, the virus is busy harming your computer in a whole other area.
- A Cloning Virus – The cloning virus is an old fashioned type of bug. When you download it, it will quickly create duplicates for .exe files you have on your computer, hoping that you’ll click on it when you really mean to click on a healthy program you already have.
- The Author Virus – When you download a virus, it usually attaches itself to a program and then runs when you run that program. The Author Virus, on the other hand, finds an .exe file and actually deletes and rewrites code so that the program is changed. Few common computer viruses run this way since the level of virus needs to be so sophisticated.
- The Bad Penny Virus – The very first computer virus to ever hit the Internet was a Bad Penny virus. This is a bug that automatically passes itself on to everyone on a network or on the Internet unless something stops it. This was the whole reason why firewalls were invented.
There are a handful of bugs out there for the Mac.
- Rewriting Virus – This bug made a habit out of rewriting some of your most needed files, as well as filling up your hard drive with all sorts of invisible files you couldn’t normally see.
- The Melissa Virus – This was a bug that hit everyone, both PC users and Mac users. It would automatically email itself to other people without permission. It can be extra harmful if you use a private mail server at your place of employment. The Melissa virus has gone down in history as one of the most common computer viruses of all time.
In the simplest of terms, a virus is a computer program that reproduces itself and attaches that copy to other computer programs. It does so in such a way that its instructions (viral code) are carried forward when the infected program is launched or when an infected disk is left in the disk drive and allowed to boot. The most troubling part about this is that it is done without the consent or knowledge of the computer user.
Viruses can be as benign as a minor case of acne, such as those that display pleasant or annoying messages, or as malignant as a full spread disease, such as those that destroy your data files and system.
There are nearly 20,000 known viruses for the PC (There are a lot less Mac viruses.) of which only 500 are currently "in the wild" (circulating on unsuspecting computers). Of that, only 20-50 are known to cause serious damage.
All viruses follow pretty much the same course of action. When the virus code is run it reproduces and infects other programs. When it starts to spread is usually a characteristic of that particular virus. Some infect each time they are run. Other more tricky ones infect when triggered by a certain time, date, function, or other external event.
Then some have an attack phase, otherwise known as a "payload," associated with them. A payload is the damaging effect of the virus that runs the gamut from deleting files or randomly changing data on your disk to playing music or creating messages or animations on your screen. When the virus inflicts its damage is also characteristic of the particular virus.
But most delay doing so only until after they've had time to spread. Some are written to spread only which is bothersome as well because they take up space and slow down your system.
A graduate student at MIT, as part of a controlled experiment he was conducting, wrote the first virus in 1986. A year later, hackers caught on and began writing and spreading viruses. By 1990-1991 the number of viruses found in the wild started to flourish. There are several types of viruses: Boot Sector, File, Macro, Polymorphic, Stealth and Resident viruses. Some viruses can possess characteristics of more than one of these types.
Getting rid of the virus will take time and your time is money. Every PC you have must be wiped and this may take at least an hour per PC. In addition every external drive will need to be cleaned as well as every e-mail with an attachment. Of course it would be cheaper if you only had to worry about those computers and external drives that are infected, but of course you don't know which ones these are; so you have to check everything.
Viruses increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by other computers and most companies now have access to their system from employee homes and other external devices.
Paid Anti-virus Programs
- Kaspersky Anti-Virus
- Eset NOD32
- Panda Internet Security
- McAfee VirusScan
- Norton AntiVirus
- Avast Pro AntiVirus
- Avira AntiVirus Premium
- Bitdefender AntiVirus Plus
- Bullguard AntiVirus
- F-Secure AntiVirus
- G Data AntiVirus
- ZoneAlarm AntiVirus + Firewall
Free Anti-virus Programs
- Avira AntiVir
- AVG Anti-Virus
- ClamWin Antivirus
- Avast 4! Home Edition
- BitDefender Free Edition
- HouseCall Virus Scan
- Immunet Protect
Here is a simple 4-step process for removing any virus
- Find a recommended virus-scan software manufacturer's Web site and install their software together with any virus updates that are available. Make sure any software you buy has free updates available regularly as you will need up-to-date protection; new viruses are produced every day.
- Run the software. The software may not be able to delete the virus, but it may be able to identify it. You can then search the Web for information regarding your specific virus by typing the name of the virus or its associated file into a search engine followed by the word "virus."
- Download and install any patches or other programs that will help you eliminate the virus. Or follow any instructions you find on deleting the virus manually.
- Run, and keep running, virus scans until there are no viruses left and then run scans regularly.
Then institute proper procedures for you and your staff!
- No downloading from the internet to business PC’s.
- No visiting inappropriate sites on company machines.
- No downloading viral attachments (jokes / videos / etc.) to company PC’s.
Computer viruses currently cause billions of dollars worth of economic damage each year, due to causing systems failure, wasting computer resources, corrupting data and dramatically increasing maintenance costs. We have access to free anti-virus tools that have been developed removing the need to buy from the multi-billion dollar industry of anti-virus software vendors that has cropped up, selling virus protection. Our software can remove all existing viruses and we are leaders in a group of computer security researchers that are actively searching for new ways to enable antivirus solutions to more effectively detect emerging viruses, before they have already become widely distributed.
Antivirus, anti-virus, or AV software is computer software used to prevent, detect and remove malicious computer viruses. Most software described as antivirus also works against other types of malware, such as malicious Browser Helper Objects (BHOs), browser hijackers, ransomware, keyloggers, backdoors, rootkits, trojan horses, worms, malicious LSPs, dialers, fraudtools, adware and spyware. Computer security, including protection from social engineering techniques, is commonly offered in products and services of antivirus software companies.
A variety of strategies are typically employed. Signature-based detection involves searching for known patterns of data within executable code. However, it is possible for a computer to be infected with new malware for which no signature is yet known; and malware is often modified to change its signature without affecting functionality. To counter such so-called zero-day threats, heuristics can be used. One type of heuristic approach, generic signatures, can identify variants by looking for slight variations of known malicious code in files. Some antivirus software can also predict what a file will do by running it in a sandbox and analyzing what it does to see if it performs any actions which could be malicious.
Antivirus software has some drawbacks. It can impair a computer's performance. Inexperienced users can be lulled into a false sense of security when using the computer, considering themselves to be totally protected, and may have problems understanding the prompts and decisions that antivirus software presents them with. An incorrect decision may lead to a security breach. If the antivirus software employs heuristic detection, it must be fine-tuned to minimize misidentifying harmless software as malicious (false positive). Antivirus software itself usually runs at the highly trusted kernel level of the operating system to allow it access to all potential malicious process and files, creating a potential avenue of attack.
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