I Run Security Software. Why Do I Still Sometimes Get Infected?

It’s a race, and we’re always behind.

Any security software can miss something. It's important to understand why this is and what you can do about it.

Question: I have virus protection always on and have the Windows firewall enabled. Why do I still get infected with some Trojan horses? I check for updates every day so I am sure I am up-to-date.

Most people believe they’re completely protected because they have an anti-malware program or additional security software.

Unfortunately, that’s just not true.

The answer is partly the nature of anti-malware software and partly the nature of “the race”.

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You can still get infected

Malware creators are always one step ahead of the tools designed to stop them. Once malware is discovered, it takes time for anti-malware tools to be updated. There really is no “best” anti-malware package. Who is “in the lead” changes often, and any tool can miss something. Of course, no tool can protect you from yourself. Use up-to-date security software, follow best safety practices, and back up regularly.

The race

I use that term — “the race” — on purpose. Combating viruses is a four-way race.

In the lead are malware writers looking for vulnerabilities and writing malware to exploit them.
Coming in second are the security software vendors, as they look for ways to detect and eradicate new malware as it appears.
Next are the application and system software vendors, who are looking to plug the security holes.
Lastly are folks like you and me, keeping our systems up to date with the latest updates to both our security software and the software that might have vulnerabilities.

As you can see, virus writers are always in the lead. You and me? We’re dead last. Hopefully close to the pack, but even so, last.

As a result, the first answer boils down to simple bad luck. It’s possible to be doing security as well as you can and still get infected, if:

Your anti-malware software has not yet been updated to detect a new threat.

Your system or application software has not yet been patched to fix whatever vulnerability the virus exploits.

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All security software is the same but different

There is no “best” anti-virus or security software. Almost all the name brands are good, but there isn’t one that detects absolutely, positively everything.

In other words, no matter what security software you run, it may miss something. Different packages may miss different things, but there’s no single package you can count on to catch absolutely everything. So it’s possible to get infected even though your anti-malware tools are completely up to date.

The harsh reality

All malware is not created equal, which is why there are so many terms to describe the variations. Some exist merely to propagate. Others exist to do damage. Some exist to silently send spam. Still others start to blur the line between virus and spyware as they install monitoring or additional vulnerabilities on your system. Some travel by email. Others travel by downloaded applications. Others can travel from unprotected 1 computer to unprotected computer directly through the internet.

No anti-malware tool can protect you from yourself. For example, if you open an email attachment that you don’t recognize and run it, you may install a virus before your security software has a chance to act. When downloading a file, if you choose to ignore a warning that your security software or firewall displays, you’re telling the software that you know better than it does what is or is not safe.

Do this

Why is it like this? It’s hard to say. Ask 10 people and you’ll get 10 different answers: hackers with too much free time, operating systems that aren’t robust enough, success in the marketplace that makes for a bigger target, and more. Of late, there’s more money to be made by infecting large numbers of machines with spam-sending bot software or malware that steals your login credentials to your bank or other important sites.

It shouldn’t be like this, but for whatever reason, it is like this and will be for the foreseeable future.

That’s why you and I must take responsibility for keeping our computers — and ourselves — safe on the internet.

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Footnotes & References

1: If you’re behind a router, as you very likely are, then you’re protected.