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Security Center / Definitions / Adware




Do you see enough advertising? Or would you like to see more? If you just can’t get enough advertising – the sketchier the better! – then you might actually like adware. But most folks would just as soon keep it off of their computers and mobile devices.

Adware is software whose primary task is to show you ads. This is typically by displaying them on your computer or smartphone as banners or popups, but sometimes also by hijacking your web browser or search forms so you go to sites they choose, not the ones you intended to use. Disreputable software tends to display disreputable ads – for example, fake get-rich-quick schemes that’ll only get you into more trouble. And sometimes it’s a way for bad actors to spy on you or infect your device with even more dangerous code.

Adware isn’t always bad – but it should be monitored

Obviously, some legitimate free software pays for itself through advertising. But not all! For example, our 100% free Sophos Home Free protects you against malware without hitting you with ads – not now, not ever.

Since advertising in legitimate software isn’t always unethical, it can be challenging to decide what’s acceptable behavior and what isn’t. That’s why Sophos Home may sometimes report adware to you as a Potentially Unwanted Application (PUA), not as malware, depending on what we know about it. We then let you choose whether to authorize or remove it. Usually, our customers choose to remove it – and usually, we’d have no argument with that choice!

Where does it come from?

How does adware get onto your device in the first place? You might download a program that seems useful, not realizing it contains an aggressive adware component. For example, we’ve recently seen free software promising you central remote control over your entertainment devices, or free access to a virtual private network, but also includes aggressive adware. The adware isn’t always there initially, either. Sometimes, after a program is installed, it may update itself to become more aggressive about showing unwanted advertising. Occasionally, you might be offered the adware as an optional install that’s included by default, which you can refuse if you’re paying close attention.

You might also become infected with aggressive adware by visiting a website that cybercriminals have compromised. The site delivers adware to you just as it might deliver ransomware or some other form of malware. And you can protect yourself just as you’d protect against other malware: by keeping your systems up to date with security patches, and using advanced anti-malware protection such as Sophos Home Premium or our free version of Sophos Home for Macs and PCs, which doesn’t include any ads or adware.

By the way: it’s important to note there’s another form of malware that’s sometimes inaccurately called adware. It’s “ad fraud” or “click fraud” software that generates fake clicks on pay-per-click ads. Those clicks lead to payments to fraudulent websites for traffic that looks as if it came from potential customers, but actually came from automated bot networks.

Devices infected by click fraud malware spend some of their resources helping criminals generate profitable fake clicks. We detect and remove click fraud malware, though this isn’t really defined as adware. We’ve mentioned it here because it’s not hard to confuse the two issues – but now, you won’t!

Adware displays advertising banners or pop-ups on your computer when you use an application. You may consider some adware to be of value. For example, some free Android apps and browser toolbars are funded by adware. Adware becomes a problem, however, if it installs itself on your computer without your consent or installs itself in applications other than the one it came with and displays advertising when you use those applications. Sophos Home detects adware and reports it to you as a potentially unwanted application (or PUA). You can choose to either authorize the adware program or remove it from your computer.

Sophos Home Free includes a free 30-day trial of Premium plus an immediate Advanced Malware Removal to thoroughly clean your computer of any current malware infections.

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