Why Do I Get Viruses When I Have Anti-Virus Software?

Why Do I Get Viruses When I Have Anti-Virus Software

So you understand the dangers of viruses infecting your machines (lost time, lost data, all-around bad news). You’ve purchased anti-virus software (either on your own or through your IT provider’s workstation management solution). You’re 100% protected now, right?

Unfortunately not. As some of you may know from experience, it is possible to be infected by a virus even if you have an anti-virus solution in place. After 24 years in the IT services industry, you can imagine that we’ve seen our share of these cases.

Why does this happen?

Below we’ll walk through how exactly anti-virus software works, why your machine can still be infected with this software in place, and how you can best prevent this from happening.

Why you get viruses even if you have anti-virus software

As we explored in another article, there are two main kinds of anti-virus software: resident anti-virus packages, and second-opinion scanners (also known as “cleaners”).

Resident packages remain active on your machine at all times. They are equipped with a collection of viral signatures (patterns) that indicate that a program is a virus. If any of these signatures are caught on your system, the software takes action to block or remove it.

Key word here: if.

While anti-virus software will be updated with new virus signatures as they’re identified, there is generally a 1-2 day period between when a virus is first let loose, and when the signature sticks. In that 1-2 days, then, you can most definitely become infected by something that your software doesn’t even know exists yet (these are known as “zero-day” viruses).

As you can see, there’s a reason that these malicious programs are called “viruses”—in the same way the flu virus will mutate in response to immunizations and continue infecting us year after year, computer viruses are constantly changing and developing in order to skirt the protective measures you have in place.

How to best protect yourself from these viruses

Besides having a robust anti-virus solution, there is one critical element to keeping your computer and your network from becoming infected by malicious software: knowing how to steer clear of risky situations.

In this article, we put together some tips on how to identify a malicious email before accidentally infecting your machine. Keep your staff educated on the latest threats, and make cybersecurity a priority across your organization and its culture.

We also recommend setting basic content filtering on your organization’s firewall to block sites that tend to be rife with malware (gambling sites, pornography sites, and so forth).

Beyond that, be sure you have a reliable and responsive support team at the ready who can contain and remediate issues immediately (even if it means wiping your machine and restoring data from a backup, which can sometimes be the only option).

We can’t protect ourselves from everything, but we can certainly arm ourselves with the tools and resources to recover quickly and with minimal disruption.

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