What Is Adware? Plus, How to Protect Yourself Against It

Adware is a type of malware that tracks your web activity and shows related ads

Adware is short for 'advertising supported software' and is any type of invasive advertising used for the purposes of generating revenue. It usually appears in the form of banners, on-screen ads, or pop-ups prompting you to click or take some type of action, and it can appear in a web browser, or in the user interface of software you've downloaded.

How Adware Works

Adware concept image
uis Diaz Devesa / Getty Images

Not all adware is bad. When used legitimately, it can be a way for developers to monetize their software, for example, showing ads in exchange for a free service or a pop-up reminding you to buy a license. The problem is that adware has proliferated across the internet and is often used by aggressive advertisers and unscrupulous companies to:

  • Track your online activities
  • Follow you from site to site
  • Target you with related ads
  • Redirect your search requests
  • Spy on you without your consent

When spying happens, adware becomes spyware. Spyware is often used to collect your data, which is then turned around and sold to third parties.

How Did Adware Get On My Computer?

There are two ways that adware can sneak into your computer.

The first way is when a website spreads adware during a "drive-by download." A drive-by download occurs when software is downloaded to your computer without your knowledge or consent. These websites often take advantage of vulnerabilities in your browser to spread adware, especially if you haven't taken some time to secure your browser.

The second way is when adware piggy-backs on top of other programs that get installed on your computer. This can often come in the form of "freeware," that has adware bundled into it for the purposes of generating revenue. If you're considering installing free software, be sure it's from an official site, and always scan it with a reputable anti-virus software product.

Never download software unless it's from the official developer's site. Adware companies often produce fake links and ads that take you to their own site, where you're tricked into downloading adware instead of a legitimate program.

How Do I Know If I Have Adware?

It's easy to see banners, ads, and pop-ups on your screen. But sometimes an adware invasion isn't so obvious. Some signs that you may have hidden adware on your computer or mobile device include:

  • Your browser slows to a crawl or crashes.
  • New tabs or windows open without you doing anything.
  • Your browser, home page, or default search engine has changed.
  • Your browser has been reconfigured with a new toolbar or plugin.
  • A download started or an app installed to your device without permission.

Sometimes adware/spyware can be silently lurking on your system without any obvious symptoms. The good news is, adware can be detected and removed, as explained in the next section.

How to Control and Remove Adware

The first step to controlling adware is awareness. In many cases, you might not know you have adware on your system, which is why it's important to be proactive about removing it. Here are the steps you can take to control and remove adware.

  • Use a reliable antivirus software program. Regardless of the type of computer you use, it's important to have some type of antivirus program installed on your system. Antivirus software for Windows or Mac runs in the background and can help detect, quarantine, and destroy adware and malicious programs on the fly. You can also use antivirus software to scan for adware on your system and remove it. This is important if you haven't used an antivirus program in a while.
  • Use a separate adware/spyware removal tool. In addition to antivirus software, you can run a separate adware/spyware removal tool on your computer. There are both free and paid versions to choose from, although too many programs can bog your computer down.
  • Keep your software up-to-date. Be sure to keep your operating system software, antivirus software, and web browser are up-to-date. This will help prevent new adware threats, ransomware, and other viruses from sneaking in.
  • Use a firewall. Keep your firewall turned on when browsing the internet. Windows firewall is turned on automatically in Windows 10 and other versions. Mac firewall is not turned on automatically, but you can do this from System Preferences > Firewall.
  • Avoid dodgy or suspicious websites. If a website looks dodgy or spammy, it's best to avoid it. These websites can contain adware as well as malicious links and code, or may can trick you into downloading infectious software.