Adware: What Is It and How Do I Protect Against It?

Janis von Bleichert
Last update
16. Mar 2023

Is your computer running slower than usual? Do pop-ups open incessantly, even when not surfing the web? If so, you most likely have an adware infection. In this guide, we'll explain what adware is, how you can prevent future infections, and what you'll need to do to be free of the problem.

What is Adware?

As a term, adware refers to a type of software that launches ads on a system, particularly in the form of pop-ups, or on the basis of your search requests. Adware also creates advertising cookies to generate revenue through affiliate marketing.

Here, it's important to note that adware is not necessarily malware, and can even have legitimate uses. For example, some 'free' programs are offered as such only if users consent to be 'bombarded' with ads (browser games are a great example of this). However, in other cases, adware finds its way surreptitiously onto a system. Whether legitimate or not, all adware is a nuisance.

Spyware the more nefarious relative of adware, collects information about your search behavior without your knowledge, using it to target you with specific ads and content.

How Does Adware Find Its Way Onto My System?

In contrast to malware, adware usually, but not always, finds its way onto your system with your permission. A few of the primary avenues of transmission include:

  • Free software
    For many freeware or shareware programs, adware is a necessary source of revenue. When downloading free software, especially from less well-known or reputable sources, there's a high risk that you'll be installing adware along with the program.

  • Browser extensions
    Free browser extensions can also smuggle adware onto your computer. For that reason, keep an eye on which extensions you install.

  • Drive-by download
    'Drive-bys' are a type of tactic developed by gangs for creating mayhem and wounding or killing rivals. The download variety doesn't involve any shooting or firearms, but it happens just as quickly, particularly when visiting a site designed to launch the software onto your system, without you being any the wiser. This is alternatively known as 'browser hijacking'.

How To Protect Against Adware?

In most cases, adware requires your consent in one form or another to operate on your system. As such, it isn't too difficult to prevent it from doing so. To help improve your chances, we recommend following a few general rules for keeping both adware and malware away:

  • Don't download unknown software
    You wouldn't accept free things from just anybody handing them on the street, would you? So, why do it online? In general, when surfing the net, you should behave as you do in real life; cautious and skeptical, particularly about things that seem too good to be true. Inform and educate yourself about programs or software you're thinking of downloading and installing, as well as where you're downloading them from. If possible, read reviews, or read up on the programs online.

  • Stay away from dubious/illegal websites
    Nearly every legitimate program is available either from its developer, or an official 'mirror', that is to say, a site that hosts the files in question and is recognized by the manufacturer as genuine/reputable. By avoiding the shady parts of the Internet, where illegal software is offered for free, you'll reduce your likelihood of coming into contact with adware or malware.

  • Use an adblocker
    Adblockers don't only block banners and pop-ups on sites you visit, they also prevent dangerous scripts from running, which can lead to drive-by downloads.

  • Utilize antivirus software
    The most proactive approach to keeping adware off your system (and all other sorts of malware) is a solid antivirus program. These scan your system not only for infections and malware, but also keep the figurative door closed to uninvited guests (potentially unwanted programs, or PUPs) thanks to their real-time protection features.

How Can I Remove Adware?

If it's already too late for prevention, and adware has made its way onto your system, fear not. You'll need to take some quick action, but, hope is far from lost! A number of means are available, both free and paid, three of which we've listed in our guide to removing adware.


Adware is definitely not the meanest threat you might face online, but probably, one of the most annoying. As long as you pay attention to which software you download and from where it originates, you don't have much to fret over. Should adware have found its way onto your system, you can follow our guide for removing it in a few, easy steps.


What is adware?

Adware is free software that launches pop-ups and other ads on your system. These can influence your search queries, and implant advertising cookies on your computer, earning affiliate provisions from you.

Is adware dangerous?

Adware is more annoying than dangerous, and can't really be classified as malware. Some free programs use adware as a legitimate source of revenue, however, adware can make its way onto your system without your permission, making it, at least technically speaking, malware.

Do I have adware on my computer?

The classic symptoms of an adware infection are unwanted pop-up ads (appearing even when not using your Internet browser) and a sudden drop in your computer's performance. Positive identification of adware is possible with antivirus programs, that will notify you of PUPs and remove them.

How can I remove adware?

In some cases, adware can be removed by simply uninstalling the program which is generating the ads. For tougher cases, there are a number of free and paid software solutions available. To find out more about these and how to remove adware, check out our guide.

Janis von Bleichert studied business informatics at the TU Munich and computer science at the TU Berlin, Germany. He has been self-employed since 2006 and is the founder of He writes about hosting, software and IT security.
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