Do Computer Viruses Spread Through Wi-Fi?

Published by Adrian in Antivirus, Web Security

These days, the internet is everywhere, not only more accessible than ever but also more affordable. And, full of viruses and malware, if I may add. But people don’t always seem to notice the latter. What, you’re saying that you can resist the temptation of connecting to a public Wi-Fi? And when you’re tapping into a private or public Wi-Fi, are you cautious with what you’re accessing? If you answered No and No, you might want to hear what I’m about to say.

Computer viruses spread through Wi-Fi. If one device within the network is infected, your device can also get infected. Sometimes, it’s a router or an access point that hosts the virus/malware. Other times, it’s one of the other devices that spreads viruses automatically or is controlled explicitly by a hacker.

So, you don’t have to do anything in particular other than connecting to a compromised Wi-Fi. Even if you don’t download anything yourself, you can still have some malware landing on your smartphone, tablet, laptop, or whatever you’re using.

What can you expect, and what can you do about it? I thought you’re going to ask, so here’s what you need to know.

How do viruses spread over Wi-Fi?

First of all, Wi-Fi is a network. And viruses pretty much spread through networks. They can do it from other devices that are already infected and connected to that network. Or they can also do it through the routers or the access points that form the network’s infrastructure.

Think of us, humans, and the viruses we get. When a couple of persons share a room, and someone has a virus, they can infect others. Either through the air, they all breathe in an enclosed space or through direct contact – when you shake hands with the ill person or touch an object he just used.

It’s pretty much the same with viruses spreading over Wi-Fi. The Wi-Fi is the enclosed space where routers and computers get together. When one of them catches a virus, everyone else is at risk. In other words, when a device without protection connects to a vulnerable network, a virus can exploit some of its ports and take control over it.

A device without protection means one that doesn’t have an antivirus or any other dedicated software!

A vulnerable network is one with no encrypted traffic and no authentication requirements!

I repeat – a hacker can install a virus through one of the device’s ports and infect the device without you downloading anything specifically.

Once the virus is dropped, it can give the hacker permanent access or do some local damage. It all depends on how it was built, with what purpose. Either way, the damage is there to stay.

Even if you disconnect from that Wi-Fi, the hacker could still have access to your device, and the device will remain infected and a source of infection for other devices from the next Wi-Fi you’ll connect to.

Can malware spread through Wi-Fi?

If we take the broad definition of malware as all the malicious software out there, it becomes evident that malware can spread through Wi-Fi in even more ways than simple viruses do.

Precisely, malware can be placed on a device directly through a port. Or it can act as an observer of the device’s ports, monitoring the incoming and outgoing traffic.

If it’s just about monitoring your traffic, once you leave the Wi-Fi, you’re supposedly out of the malware’s negative influence.

Still, this can be more dangerous because depending on what type of information you access while connected to that Wi-Fi, you can be exposed more or less.

This is the reason why you are often strongly advised not to log in on websites, not to make payments, not to access bank details, not to check your e-mail, and not even check your social media accounts when connected to a public Wi-Fi.

Bear in mind that if you connected to Wi-Fi and got a virus or malware that was physically installed on your device, your device will be permanently compromised. The vulnerability remains long after you left that network, although you have only read the news or other general information that you considered harmless.

What type of attacks do hackers use through free Wi-Fi?

Like I said, free Wi-Fi is getting more and more popular these days. We get to see and access hotspots so often that we don’t think twice about it.

What can go wrong if you only read your e-mail, browse the news or check a social media account? A lot of things can go wrong, actually!

MitM attacks – this stands for man-in-the-middle. It is the most common type of eavesdropping attack. And it implies that someone can take a peek at what you’re doing on that network anytime, without you even knowing it. It’s because the information transferred between your device and the service or website that you’re accessing is not secured.

Setting up rogue hotspots – a rogue Wi-Fi is the evil twin of the network you thought you’re connecting to. Cybercriminals often set up a fake Wi-Fi access point. The face network pretends to be the legitimate hotspot offered by a hotel, a coffee shop, or whatever. Again, any information you disclose while using the rogue Wi-Fi can be intercepted.

File-sharing vulnerabilities exploits – do you have the file-sharing function enabled on your device? If so, a hacker can take advantage of it. Basically, that function can be used to allow the silent installation of malware or even ransomware. Unless you disable the file-sharing before accessing a public Wi-Fi, there’s a high risk that a hacker can access your device through that network and install malware on it even if you only browse the news!

Packet sniffers – again, this is about monitoring the traffic, identifying valuable personal information, and intercepting it. If login credentials to e-mails or bank accounts, or other important accounts are used during that connection, the sensitive data can be captured by using such packet sniffers. This way, the hacker will gain full control of your compromised accounts and access them at his discretion long after you’ve left that hotspot.

How to prevent getting infected from a free Wi-Fi

Knowing how viruses and malware travel via Wi-Fi and what types of attacks are commonly orchestrated, it becomes obvious what you can do to protect yourself. Simply put, you can prevent getting infected from free Wi-Fi if you do as many of the following things as possible:

  1. Use a VPN to make sure your connection is safely encrypted;
  2. Install Antivirus software on your device and make sure it is up to date;
  3. Use a web filter for enhanced protection while surfing the web from a browser;
  4. Make sure that the Wi-Fi auto-connect option on your device is disabled;
  5. Make sure that the File-Sharing option on your device is disabled;
  6. Try, as much as possible, to keep the Wi-Fi and the Bluetooth disabled when you don’t need them;
  7. Connect, as much as you can, on password-protected Wi-Fi networks;
  8. Don’t access sensitive information and avoid logging in to any of your accounts;
  9. If you access a website and need to log in anywhere, make sure it uses HTTPS;
  10. If you log into any account, always log out before closing the web browser or the app.

I know these are quite a few rules, and many of them take out the fun of using free Wi-Fi. But if your purpose is to stay safe, you’ll want to leave the fun for later, when you get to a secure internet connection.

Since computer viruses easily spread through Wi-Fi, it’s quite a high price that you might have to pay for your boredom cure.

At the end of the day, nothing is as important for you to be willing to take the risks I just described to you above. And if it’s work-related and cannot wait, hopefully, your employer has taken all the precautionary measures to allow you a safe remote connection…