Last year, I posted an offer for a free 1-year subscription to an anti virus product. Since that offer expired, I’ve had many questions about free products. Online virus scanners seem to be of interest. These online tools can be a nice resource even if you already installed an AV tool.

Most people are familiar with the installed version of virus scanners. New PC’s often include trial packages of Symantec or McAfee. These same companies and others offer free online virus scanners that work with your web browser. Although related to the installed counterparts, they do differ.

Can Free be Good?

“Free” is one of those words that invoke interesting reactions. Once you mention it, someone will say, “You get what you pay for”. You also get a few people who claim the services are free because these companies are sucking the contents of your PC and selling your personal data.

I can see where people might leap to some of these conclusions. For example, these scanners are not as effective in some areas as stand-alone products. Online virus scanners are designed to detect current threats to your machine whereas stand-alone programs provide other layers of protection like real-time scanning of incoming email and so forth. Some of these online services do not clean infected files.

As for the companies getting personal data, yes it can happen under certain circumstances. If you were to read the End User License Agreements, you might see text such as the following:

The Software contains a function, which serves to collect samples of new computer viruses or other similar harmful computer programs (the “Infiltration”) and the subsequent dispatch thereof to the Licensor. This includes, for example, information about the computer and/or platform on which the Software is installed (the “Information”). The Information may contain data (including personal data) about the Licensee and/or other users of the computer on which the Software is installed, information about the computer and operating system, suspicious files from the computer on which the Software is installed, and files affected by the Infiltration and any information about such files. The Licensor shall use the obtained Information and the Infiltration only to review the Infiltration and shall take reasonable measures to keep the obtained Information confidential.

The above paragraph does reference the risks involved, but these are not unique to online virus scanners. The same issue can occur with many types of error reporting services or even if you were to send a virus file to a company for analysis. One difference is this submission can be automatic with some online scanners.

In some cases, such as Panda’s ActiveScan, you need to provide an email address before using the scanner. They state the address is to send you promotional material, but you can opt out.

Advantages of Online Virus Scanners

One advantage to using online scanners is they give you another way to tackle an existing threat. Last year, a friend picked up a nasty computer virus, which disabled her antivirus program. It wouldn’t let me update her files. Using an online scanner, I was able to identify and remove the virus.

Another benefit is online scanners have simpler interfaces and fewer choices. You don’t need to worry about scheduling or updating your virus signature files. These are on demand scans with current signature files. I’ve seen many computers where antivirus programs were improperly configured. Outdated virus signature files are about as effective as last year’s flu shot.

Disadvantages of Online Virus Scanners

There are some distinct disadvantages to consider which may limit your selection or make you reconsider a stand-alone product. The biggest drawback is that an online scanner only protects you from what is already on your machine. It does not offer real-time virus protection. Other disadvantages apply to some of the services.

• May require you to install an ActiveX component
• May just work with a specific browser
• May not clean/remove all threats
• May not be able to select which folders or drives to scan
• May not scan all file types

Differences between Online Scanners

There are plenty of differences between these products. Too many for this article, but I think it comes down to a few key questions:

• Can the tool clean or remove the infected files?
• Can you select which areas to scan?
• Do you have to download an ActiveX component?

Some of the services would detect problems, but not act. For example, Symantec and McAfee provide good detection, but you’ll need to scour their websites to find the steps to remove the threat. Panda took a different approach and offered the option to clean your PC for a fee.

Another noticeable difference was the ability to select specific areas to scan. Some services like ESET had one scanning option, your entire computer. The opposite approach was taken by Kasperksy who offered the most flexible system. You could scan your whole computer, single file or a functional area such as My Mail or My Documents. Sadly, some services such as McAfee didn’t recognize other drive partitions. Their version of “My Computer” was limited to my C: drive, but my test notebook had two other partitions.

All the services needed you to download one or more files. They all provided a combination of scanning with Internet Explorer with ActiveX components. Trend Micro thoughtfully provides a Firefox and Java alternative.

Installing an Online Scanner

If you’re apt to read the EULAs for these services, you will see a common denominator. They all want you to back up your PC first. Good advice for any software installation, but one also hopes you have a previous backup, which is virus free.

The services have three common phases: setup, scan and scrub. The set up process includes agreeing to the terms of service and installing the necessary files. The scan process may allow you choose which folders to scan. Finally, the scrub process includes acting on the threats the scanner identified. Some services let you take specific actions on identified threats, but some want you to buy their product.

Company	Browsers	Clean	Scan Folders	Files	Scan Time (Minutes)
BitDefender	IE	Y	Y	336224	101
ESET	IE	Y	N	327940	122
Kaspersky	IE	N	Y	98152	184
McAfee	IE	N	N	60055	48
Microsoft	IE	Y	N	NA	296
Panda	IE	N	Y	643078	136
Symantec	IE	N	N	95938	56
Trend Micro	IE or FF	Y	Y	NA	93

NA = virus scanner did not provide this info.

Although not shown in this table, all but two services found “threats” with my PC. On one extreme was Panda, which listed 136 threats. In looking at the saved analysis, they were all cookies, which I didn’t consider a threat. Symantec picked up two items from an old toolbar I no longer use that I think were “false positives”. This sometimes happens when developers use the same file names as real threats. Trend Micro identified a file that is linked to a keystroke recorder in one of my demo programs. One reason for the differences is some of these services also scan for threats other than viruses such as spyware.

You’ll also note that each service scanned a different number of files. Again, it’s hard to draw comparisons between the services. Some services don’t state which file types they scan or how they count. For example, the Panda count was much higher than all the others were. I suspect they may count each file within a compressed file but others might count that file as one file.

You can also see the scan times varied considerably. Without knowing the details of how each service scanned my PC for viruses, it’s hard to put a value on this number. It could be one scan engine is more efficient than other or it could be a function of how many files were scanned. Neither Microsoft nor Trend Micro showed how many files were scanned.

Tips for using Online Virus Scanners

Although these services are easy to use, I think there are some tips you can use to make the experience even better.

1. Clean your PC before scanning. Even on my small notebook, a scan took between one and five hours. That time can be shortened if you clean out files you no longer use. In retrospect, we should’ve used CCleaner to remove unwanted files.

2. If you’re using one of these services as a second opinion to your virus scanner, make sure to turn it off before scanning. You may also have to run these services as an administrator.

3. Check your options. Some of these services offer more options you may wish to use. For example, if the program can’t remove an infected file you may want it deleted or you may wish to be prompted for an action.

4. Run the online scan during the evening or when you’re not using the PC.

If you don’t have an anti virus program, you should definitely try one of these online virus scanners. If you already have a program, these online resources are a great way to see if anything is getting through that shouldn’t.

Related Articles:

• The Basics of Web Browser Cookies
• What is ActiveX