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Adware: what it is, how it works​,​ and how to protect yourself

It’s a type of malware that sneaks onto your device with one annoying purpose: to inundate you with unwanted advertisements and pop-ups. We’re talking about adware of course. At its most sinister, it tracks you, so it seems to know all about you as it serves up personalized ads. How does it spread, why do adware authors bother with this horrid creation and how can you tell if your machine is infected? We reveal all below. Before you get started, consider expert online security, like ​Avira Free Security​. It helps keep you safer from all manner of online threats and includes a range of privacy and performance enhancers.

 

What is adware? 

One minute you’re surfing the web as usual. The next, your web browser seems to have gone bananas and turned your screen into a circus of endless pop-ups and ads that come sliding in like acrobats…That’s adware. The name says it all really. This “advertisement-supported software” is invasive and unwanted, making it malicious (or malware) too. It’s designed to turn your computer screen into its personal playground for endless ads and usually affects desktop computers, but mobile devices aren’t immune either. Adware can be more than a distraction or annoyance—it may even manipulate users and open a back door for other online threats.

How does your computer get infected with adware? 

There are two ways in which adware is most likely to sneak onto your computer—and both require your help and holes in your online security to be successful.

Firstly, you unwittingly download a program that contains adware. Usually, this will be shareware or freeware that secretly installs adware in the background. So, while it may be tempting to get something for free, you may end up paying the price in other ways. Bear in mind that free software is allowed to contain some ads that come bundled with the program and are displayed in the way the developer intended. It’s how they make some money off otherwise “free” software. However, a third party illicitly adding software to your device without your consent is not legal! This cyberthreat technique of bundling a malicious program into a software bundle that you’re legitimately downloading is called a drive-by-download.

Secondly, you might just be visiting a website. It could be an unsafe website (look out for a “not secure” message in the site’s URL) but even legitimate websites can be loaded with malicious pop-ups or ads. Just clicking to close them can trigger a malware download. As soon as this adware has made itself at home on your machine, it starts misbehaving by gathering your information, redirecting you to malicious websites, and hurling advertisements at your browser. This method of infecting devices is called a drive-by-download and merely visiting a compromised website can trigger an automatic download of unwanted or malicious software.

Whatever malware they’re trying to spread, hackers are gleefully waiting to exploit vulnerabilities in your software or operating system. That’s why comprehensive anti-threat protection from trusted online security specialists is vital. Ideally, it should include a software updater too as outdated programs may contain security loopholes known to cybercriminals. Avira Free Security bundles Avira Free Antivirus with a Software Updater, Password Manager, VPN, and more so you can easily embrace an end-to-end approach for enhanced online security and privacy.

 

How does adware work? 

Like so many things in life, adware exists to make money. It hopes that you’ll (intentionally or accidentally) click on an advert it throws your way because every click generates revenue for the creator and distributing vendor. Here’s how the business model typically works: 

Pay-per-click (PPC): The adware owner and distributor are paid every time you open an ad. 

Pay-per-view (PPV): They’re paid each time an ad is shown to you.

Pay-per-install (PPI): They’re paid each time bundled software is installed on a device. 

Ads aren’t always shown at random. Adware can track your search and browsing history to display targeted ads relevant to you. Plus, any information that’s hoovered up by the adware (like your location and browsing history) is an additional source of income if it’s sold to third parties. It’s all business, and you and your data are a hot commodity.

At its most harmless, ad-generating software is merely a nuisance but that’s no reason to take it lightly. At its worst, adware is a threat to your online privacy and cyber security. It can be bundled with other malware, like spyware and ransomware, plus who knows where your personal details could end up? In the wrong hands, that may lead to identity theft, where a cybercriminal hijacks your online accounts to impersonate you.

What does adware do to your computer (behind the scenes)? 

What does adware do to your computer (behind the scenes)? 

Pop-ups inevitably “pop” to mind first, but there is a far broader range of consequences, and some won’t be immediately apparent as adware loves to operate behind the scenes.

  • Pop-ups that seem infinitely self-generating
    You won’t fail to notice these—imagine a swarm of ads suddenly appearing! When you close one ad, another opens, and you’ll fight a losing battle trying to clear your screen. 
  • A slower computer and other performance issues
    When your machine is kept busy loading and showing you advertisements, it has fewer resources for all the processes you’re trying to run, which inevitably slows down ​​​​your computer’s​​​​​ ​​​performance​. Browser pages and apps might also open more slowly, and your device freezes and crashes more frequently.
  • Secret spying
    As mentioned previously, malicious adware can behave like a covert detective. It monitors your activity online and collects personal information to map you and your purchasing prowess for targeted ad campaigns. (Strategies like drive-by downloads and fake software can also lead to keyloggers being installed on your computer. These log every keystroke to gather up information like passwords).
  • Man-in-the-middle attacks (MITM)
    During a MITM attack, the threat actor puts themselves between a user and an application, to intercept their communications and data exchanges. Lenovo once famously sold computers preinstalled with Superfish adware that could intercept encrypted traffic for every website the user visited.
  • A disappearing data allowance
    Downloading advertisements can eat into your monthly mobile data allowance. Always monitor your data usage and be suspicious of sudden spikes in activity that can’t be attributed to, for example, photos, videos, and online games you’ve been sending, watching, or playing.

Meet the types of adware

Most adware is annoying yet harmless while some can do more damage. Here is a breakdown of the usual suspects you’re likely to encounter:

Legitimate adware (the sort-of good): Allows you to consent to ads and software promotions. This helps the developer cover the costs of creating their software and offering it for free—so users willingly put up with adware to get a free download. Legitimate adware can also let users choose to allow it to collect marketing information and many people find the personalised ads useful. It’s important to remember that legitimate adware is a legal way to provide a free product (so long as all the downloads are consensual!). 

Potentially unwanted applications or PUAs (the potentially bad): If you didn’t choose to include a program in a download, it could be potentially unwanted and could entera legal grey area. The extent to which it turns out to be illegal or malicious depends on the goals of the software developer and the distributors. There are different flavours of PUA: 

  • Legal deceptive adware PUA may deliberately make it tricky to opt out of installing third-party software. Even legitimate adware sometimes uses this method and while it can be frustrating, it’s not necessarily illegal—as long as the creator hasn’t deliberately included infected ads or software. Sadly, some adware can deliver disguised malware, so even the software developer may be none the wiser. 
  • Legal abusive adware PUA is the type we usually associate with adware as it bombards you with ads. This endless circus of pop-ups may be in the adware itself or come in packaged software via web browser toolbars. If no malware is present, the only damage is likely to be to your sanity and productivity, making this type of adware legal (surprisingly!). Beware of ads for pornography or miracle cures like fast weight loss, as they tend to be most likely to harbour this type of ad infection.
  • Illegal malicious adware PUA funds itself via third parties who distribute malicious software like spyware and viruses onto unsuspecting devices. The malware may be intentionally hidden within the adware, the accompanying software download, or the website that advertises it.

There’s no such thing as a free lunch: We tend to associate adware with the worst members of its family, but in fairness, it can also be a legal way for developers to provide something for “free”—just remember that very few things in life will truly cost you nothing.

What’s the difference between malvertising and adware?

Adware gets an even worse rep as it’s often confused with malvertising. While adware sends ads onto devices to generate clicks, malvertising injects malicious code into online ads. Click on the ad and the malicious software could embed itself into your device to damage it or steal your data. Even reputable websites can accidentally display malvertising so trust noone and always have reputable antivirus in place! Remember that even the New York Times, BBC, and Newsweek have all fallen prey to ads laced with malicious software that hijacked readers’ computers and demanded ransom.

How can you tell if your device is infected with adware? See this quick checklist

Being inundated with endless pop-ups, ads, and banner offers is a strong hint but there are other tell-tale signs to look out for. You may experience persistent problems if you don’t remove adware.

  • Your browser has significantly slowed down. Browser pages open more slowly, and apps take ages to load.
  • Your operating system, browser, and other programs are crashing frequently. 
  • The battery on your device is draining much more quickly.
  • Your homepage suddenly looks different and you’re sure you didn’t change it.
  • You see multiple extensions have been added to your browser without permission.
  • Websites you visit are filled with pop-ups. 
  • It’s tricky to surf as you’re constantly being redirected.

How do you get rid of adware?

While blocking certain kinds of scripts from running in your browser may help thwart adware, it’s usually written with the same code as legitimate websites and services. Disabling those scripts can seem like a quick fix but could mean that the website won’t function properly. Here are some tips on how to spot and remove intrusive ad programs. It all depends on the type of device you use—but before you gleefully delete a suspicious program, do a quick web search to make sure that it isn’t, in fact, necessary to the functioning of your computer! 

  • Remove adware from a PC: If you know which program is causing the adware, simply remove it the same way you would any app: Right-click on the Windows Start menu and then click Apps and Features. Scroll to the program you want to be rid of and select Uninstall. Use Avira Free Antivirus, included in Avira Free Security, to manually scan for adware and malware. It also helps keep you safefrom malicious URLs and new and emerging threats (for free!).

 

  • Remove adware from a Mac: If you use the Safari browser, you can use the built-in pop-up blocker. Navigate to Settings. See the Websites tab and configure your system preferences for pop-ups. Then go to the Security tab and toggle the Fraudulent website warning feature. Also, check your Safari extensions tab for any unwanted extensions and delete them. To finish, restart your browser or Mac. If you think that you already have adware, restart your Mac in safe mode. Search through your applications and look for unfamiliar software or anything that’s been recently installed. Mac fans, remember that Avira Free Security for Mac helps keep you safer online, scans your device for threats, and helps keep your software safely updated.

 

  • Remove adware on Android: Activating Safe Mode will help remove adware from your Android device. Here’s how: Hold the power button down and then select Reboot in Safe Mode. Then go to Settings and choose Apps & Notifications to see all the apps installed on your device. If you don’t recognize an app and it’s safe to remove it, click on Uninstall. Did you know that Avira Antivirus Security for Android helps scan and better protect your phone from millions of mobile online threats? The Identity Safeguard offers identity protection and helps check if your email shows up in a known security breach.

 

  • Remove adware on iOS: All devices running Apple’s iOS operating system regularly receive updates to help protect them from adware. Here’s how to remove unwanted programs if you still think your iPhone or iPad could be infected: Turn off your device and then turn it back on. Hold the volume button as it boots back up. Go to System Settings and then General and Storage where you can look for suspicious apps. Avira Mobile Security for iOS is packed with free features to help protect you from a range of online threats, including the latest malware and phishing sites. It also helps keep your operating system up to date and the Privacy Manager can prevent Siri from accidentally recording your conversations.

 

If you’re still concerned that more than adware could be lurking on your device, find out how to run a malware test. 

Help protect yourself from adware, and more

Like malware, adware strains are always evolving and it’s better to help prevent an infection than attempt to cure it later. Practising good internet and computer maintenance habits isvital in keeping your device and data safer from cyberthreats, and unwanted apps and keeps ads at bay.

Be ultra-cautious when clicking on links, pop-ups, or opening attachments, and trust no one—even friends can unwittingly send you malware or be impersonated on social media.

And did you know that all software is a work in progress? Developers are always discovering vulnerabilities and patching their wares to help protect you from cyberthreats—that’s why regular updates are essential. It also pays to stick to legitimate sources of downloads, services, and goods. While pirated or cracked software and games may sound tempting, they’re not just illegal but could put your device and data at risk. Also, anything outside of an official app store is more likely to be laced with the unknown. So, take your time! It’s tedious but read all terms and checkbox agreements before clicking next when you’re installing software, or you could end up with PUAs. 

In the daily battle to stay safer online, your online behaviour and a reputable cybersecurity solution are non-negotiable lines of defence. That’s why multi-layered protection like Avira Free Security blends antivirus with a software updater, VPN, password manager, and more, so you can help keep adware and hackers at bay while helping to speed up your device.

 

This post is also available in: GermanFrenchItalian

Freelance Cybersecurity Writer
Nicola Massier-Dhillon is an experienced cybersecurity and technology writer. Nicola spent many years as a senior copywriter and creative lead in marketing agencies, crafting compelling content and campaigns for major tech brands like HP, Dell, and Microsoft. She originally hales from Namibia and is a passionate advocate for the conservation of wild habitats--also putting her words to work for charities, eco-tourism, and healthcare. Nicola spends her time looking after her (wild) twins, rescue cats, and a crested gecko called Giles.
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Help protect yourself from adware and online threats with Avira Free Security.

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Help protect yourself ​from ​adware and online threats with Avira Free Security for Mac.

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Because even mobiles face adware and online threats: Avira Mobile Security for iOS.

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Because even mobiles face adware and online threats: Avira Antivirus Security for Android.