What is adware?

What is adware? A comprehensive guide

Adware is a type of software that displays advertisements on your device, often without your permission. The adware definition refers to software that not only shows unwanted ads but may also collect user data, track browsing habits, and sometimes serve as a gateway for more malicious programs, making it important to understand its behaviors and impact.

While some adware supports free applications by showing ads in exchange, other forms are more invasive and operate without your consent, tracking your activity and compromising your privacy.

This guide explains what adware is, how it works, the risks it poses, and how to protect your devices.

What is adware?

Adware, short for “advertising-supported software,” is a program that delivers unwanted advertisements to your device. These ads often appear as pop-ups, banners, or auto-playing videos. In many cases, adware also collects information about your browsing habits to display targeted ads. Adware exists to generate revenue for software developers, either by displaying ads or collecting user data.

When adware installs itself without your knowledge or collects data without your consent, it is considered malicious software. Adware work involves monitoring user behavior and delivering targeted ads; it is unwanted software designed specifically for this purpose. Some users download adware knowingly, often in exchange for free software or discounts.

Types of adware

There are several types of adware, including:

Legitimate adware

Some software includes ads to offer free access. These applications typically inform users and offer a paid version without advertisements. Adware programs can be either legitimate or malicious, so identifying whether an adware program is safe or harmful is important for effective removal.

Potentially unwanted programs (PUPs)

These are programs that users may not intend to install. They are often bundled with free software and may include hidden adware components. Potentially unwanted applications (PUAs) are a type of potentially unwanted program, frequently bundled with free software, and can range from benign to problematic depending on their behavior.

Malicious adware

This type of adware behaves like spyware or malware. It installs without authorization, tracks user activity, and may redirect users to malicious websites. To better understand the differences, read our guides on what malware is and how spyware works.

How adware works

Adware operates in several ways. It often integrates advertisements directly into the user interface of software applications, displaying pop-ups or banners that users encounter during normal use:

Bundled software

Free programs may include adware as part of the installation process. Users who do not opt out during setup may unknowingly install it.

Infected websites

Visiting certain websites can result in automatic adware installation through drive-by downloads.

Fake apps

Malicious applications, especially on mobile devices, may contain embedded adware.

Browser hijacking

Some adware changes your browser settings, such as your homepage or default search engine, to generate revenue from ad clicks. In some cases, adware acts as ad clicker software, covertly clicking on ads without your consent to commit ad fraud and potentially lead to unauthorized subscriptions.

How adware spreads

Adware often spreads without the user’s knowledge, frequently as a result of distribution methods used by adware vendors. Adware vendors commonly bundle adware with freeware or shareware programs, or distribute it via infected websites, sometimes installing it on a user's device without the user's knowledge. Common infection methods include:

Software downloads

Free or pirated software often contains hidden adware, which can infect a user's device through these methods.

Drive-by downloads

Certain websites can automatically download and install adware without user interaction. You can learn more about how drive-by downloads work and how to protect yourself in our dedicated guide.

Compromised websites

Even legitimate websites can host malicious ads that lead to adware infections.

Existing malware

If your device is already infected with malware, it may install additional adware.

Risks associated with adware

Adware can cause a range of problems, including:

Slower system performance

Adware consumes system resources, which can slow down your device. Too many ads can also cause technical problems such as crashes and freezing.

Privacy invasion

Some adware collects sensitive data such as browsing history, passwords, or location.

Security vulnerabilities

Malicious adware may serve as a gateway for other forms of malware. Certain types of adware can lead to additional malware infections, compromising system security and performance.

Misleading ads

Users may be redirected to fraudulent websites that attempt to steal personal or financial information.

Abusive adware

Abusive adware manipulates user consent and bombards users with unwanted advertisements, often making it difficult to opt out and creating vulnerabilities.

Signs of an adware infection

Your device may be infected with adware if you notice signs of unwanted adware, such as:

• Frequent pop up ads or banner ads

• Slower browsing or device performance

• Changes to your homepage or search engine

• New toolbars or browser extensions you did not install

• Redirected search results

• Web pages displaying incorrectly or appearing altered

• Increased battery usage on mobile devices

Mobile adware

Mobile adware is a form of malicious software specifically designed to target mobile devices like smartphones and tablets. Unlike traditional adware found on computers, mobile adware often sneaks onto your device through free software downloads, mobile apps from unofficial sources, or by visiting malicious websites. Once installed, this unwanted software displays persistent unwanted advertisements and pop ups, often disrupting your user experience and making your device difficult to use.

Mobile adware doesn’t just clutter your screen with ads – it can also collect personal data from your device and generate revenue for its creators by tracking your activity or forcing you to view or click on ads. This can lead to slower device performance, increased data usage, and even expose your device to other malicious programs.

To protect your mobile devices from mobile adware, always be cautious when downloading free software or mobile apps, especially from sources outside official app stores like Google Play. Avoid clicking on suspicious links or pop ups that appear while browsing. Most importantly, install antivirus software designed for mobile devices to help detect adware and block malicious software before it can cause harm. By taking these precautions, you can reduce your risk of adware infection and keep your mobile device running smoothly.

How to remove adware

There are two primary methods for adware removal:

Automatic removal

Use reputable security software with an adware blocker feature. These programs can scan your system, detect adware, and remove it efficiently, while also preventing adware from infecting your system in the first place.

Manual removal

Advanced users can manually remove adware by:

• For Windows users, uninstalling unknown or suspicious programs from the Control Panel; for Mac, use the Applications folder

• Resetting browser settings to remove extensions and search hijackers

• Deleting temporary files

• Reviewing and removing unauthorized apps on mobile devices

How to prevent adware

Prevent adware infections by adopting the following best practices:

• Only download software from trusted sources

• Always choose custom installation settings and deselect unwanted programs

• Keep your operating systems and software up to date

• Use an ad blocker to reduce exposure to malicious ads

• Install and maintain reliable antivirus software

• Do not click on suspicious ads or pop-ups

Conclusion

Adware can range from minor annoyances to serious security threats. Some programs rely on ads to support free services, but others invade your privacy, collect sensitive data, and expose your device to additional risks.

By understanding how adware works and following secure digital practices, you can protect your devices and maintain control over your personal information.