Adware, short for advertising-supported software, is software designed to display ads on devices, often through pop-ups or banners, to generate revenue. Under the adware definition software is included that can operate with user consent as part of free services. Unfortunately, this “consent” is often hidden in lengthy terms and conditions so that users overlook it or are tricked into consenting.
The objective is usually to deliver personalized ads by collecting browsing history, search patterns, and sometimes even location data, something that can raise serious privacy concerns.
In a common scenario, a user downloads and installs free software that comes together (is “bundled”) with adware components. Another way of infiltration is through the exploitation of browser vulnerabilities. Traditionally, adware was usually seen on desktops, but today it is increasingly targeting mobile users through apps as well. Successfully installed adware tracks online habits to personalize ads, but sometimes, the collected data is sold to third parties.
Over time, the meaning of “adware” has become interlaced with that of a virus, but the two are not the same. A computer virus is a type of malware that self-replicates and spreads for malicious purposes, while adware has as a primary focus the tracking of user behavior. While mainly intended for advertising, certain aggressive forms, often called “adware viruses,” can act like malware, embedding themselves into systems without permission and making removal difficult.
Adware is not inherently malicious. In cybersecurity, what makes it notable is its intrusive behavior, tricky consent practices, and capacity to compromise user privacy.
Upfront about its purpose, it lets you use free software in exchange for showing you ads and gathering marketing information. Users who download it agree to it, and the software follows the law. While it's not harmful and consensual, too many ads can slow down your device.
Browser hijackers are a more aggressive type of adware that changes your web browser settings without asking. They might switch your homepage, change search settings, or add toolbars you don't want. They often send you to websites that pay them money for your visit, bringing them ad earnings. Not only does this make your web browsing less enjoyable, but it also invades your privacy by tracking your online activity.
Adware is the most common type of PUP - a broader category that also includes various unwanted software like browser hijackers, toolbars, and even some system optimizers. Some PUPs monitor your browsing habits and collect data. They might alter your homepage or search engine or install unwanted toolbars. PUPs typically get installed when users inadvertently agree to them during the installation of other software through pre-selected checkboxes, confusing language, or users simply rushing through the installation process without paying close attention.
This type does more than show ads - it might install harmful software, steal sensitive information, or create security holes in your system. The goal is to access valuable data or control your device without permission. As it uses tricky methods to avoid being found, it is considered a malware.
Under this type is included the software that tracks your activities and collects data (like your browsing habits). Without your consent, this data might be sold to advertisers or other companies to make money.
Mobile adware is a more recent type that also shows unwanted ads but on smartphones and tablets. It can sneak onto your device without you noticing because it often hides inside apps that seem safe - like games or tools. After it is installed, it can display annoying ads everywhere, even outside the app. This can seriously slow down your device, drain battery life, or eat into your data plan.
But that's not all. Mobile adware might also click on ads in the background to earn extra money, leading to unexpected charges or using more data. It can also access personal information like your contacts and messages because it asks for permissions when you install the app, and you might not realize what you're agreeing to. Sometimes, it even lets in malware that can steal important information, putting your data at risk.
This problem is especially challenging on Android devices, which allow apps to be downloaded from third-party sources. Even official app stores can occasionally contain infected apps. Some adware is so tricky that it stays on your phone even after you try to reset it. That's why it's important to be careful about where you get apps. Also, pay close attention to the permissions they ask for, and use good security tools to protect your device.
For keeping your devices safe, it is important to understand how adware acts and how you can stop it:
|
Infection Cause |
How It Happens |
How to Prevent It |
|
Bundled Software Installations |
Users install software without reading the details, accidentally agreeing to install adware together with some free download. |
Always read installation screens carefully. Choose "Custom" or "Advanced" installation options and uncheck any extra software. |
|
Free or Pirated Software |
Illegally copied or “cracked’ software can hide adware inside. This is especially risky on phones. |
Only download software from official, trusted sources and avoid pirated software. |
|
Malicious Ads (Malvertising) |
Clicking on ads from untrustworthy websites can automatically download adware. Even well-known websites can sometimes have bad ads. Older devices are at a greater risk. |
Use ad-blockers and be cautious about which ads you click. Keep your device and browser updated. |
|
Compromised Sites and Drive-By Downloads |
Visiting a hacked site can download adware if your browser has weaknesses. This affects computers and mobile devices. |
Update your browser and OS regularly. Use security software to detect and block threats. |
|
Third-Party App Stores |
Apps from unofficial app stores can have adware. They may ask for unnecessary permissions so they can show ads or collect data even when you're not using the app. |
Download apps only from official app stores. Check app permissions and only grant what's necessary. |
Use reliable security software such as antivirus, antimalware, or security programs that can find and block adware.
Keep everything updated as regular updates include patches for security vulnerabilities, including zero-day exploits - flaws that attackers can exploit before a fix is available.
Adware might seem merely annoying, but the truth is that it can cause serious problems. What makes it particularly worrying is the fact that it often operates secretly, so you might not realize it's there.
Adware slows down your device by using important resources like the processor and memory. This makes other programs run slower, increases loading times, and can even cause your device to crash. On laptops and mobile devices, it can drain the battery faster because the device is working harder.
It can consume your data plan by downloading lots of ads, potentially increasing your phone bill, especially if you have limited data. You might experience intrusive pop-up ads, new browser tabs opening on their own or being redirected to websites you didn't intend to visit, which could expose you to additional security risks.
Adware can pose significant privacy concerns. Some types track which websites you visit and what you search for, then sell that information to advertisers or use it to show you targeted ads. This is like spyware because it's monitoring your activity without you knowing.
It can change your browser settings or install unwanted toolbars, making your device less secure and more vulnerable to other malware.
Can adware be harmless, or is it inherently good or bad? While some adware supports free apps by displaying ads (like commercials on TV channels), most are risky and go beyond mere annoyance. If it installs itself without your permission or changes your settings without consent, it can harm your device's performance and invade your privacy. In some cases, it can even pave the way for more dangerous malware, which can damage your device or steal sensitive information. Therefore, even if some adware seems harmless, it's generally best to avoid or remove it to keep your device running smoothly and protect your personal data.
Detecting unwanted advertising software can be tricky because it often looks like you are having normal computer problems. Here are some simple tips for finding adware based on common signs of infection:
1. Unusual Ads and Pop-ups
Seeing lots of ads or pop-ups, especially when you're not on the internet, is a clear warning sign. Look for changes to your homepage or search engine or new toolbars you didn't add yourself, as adware might change these to send you to certain websites. It can also make web pages load slowly or in unusual ways.
2. Unknown Programs
Look at all the programs on your device and see if there's any you don't recognize, especially new ones. Adware often sneaks into your device together with free apps under apparently harmless names. Another thing to check for anything unfamiliar is in your browser add-ons or extensions.
3. Device Performance
Use tools like Task Manager (on Windows) or Activity Monitor (on Mac) to see if any programs are using a lot of power or memory. If your device is slow or acting weird, it might mean adware or other bad software is running without you knowing.
4. Mobile Device Signs
On phones and tablets, adware can cause high data usage or make your battery drain fast because it runs in the background all the time. If you notice these problems or if an app you open asks for excessive permissions, run a security check on your device.
5. Security Scan
Use trusted security software to do a complete scan of your device and find hidden adware that you might miss on your own. Good anti-malware/antivirus security tools will check everything and help you remove any hidden threats safely.
If you see signs of adware, start by turning off any suspicious programs or add-ons and disconnecting from the internet to stop any more data from being shared. Then, run a full system scan with your cybersecurity software to get rid of any hidden problems. Don't try to delete unknown files by yourself, as you might accidentally remove important system files - it's best to let reliable security software handle the removal safely.
One of the first adware programs, Gator, was often bundled with free software downloads. It tracked browsing to serve ads through controversial data collection practices and a lack of transparency.
2. Superfish (2015)
Superfish was pre-installed on some Lenovo laptops. It injected ads into secure web pages and compromised HTTPS. This revealed the risks of pre-installed software and how serious a breach can be.
3. MobiDash (2015)
MobiDash is a family of mobile adware often found in Android apps from unofficial app stores. It displays intrusive ads, including full-screen ads and ads outside of apps, impacting device performance and battery life. MobiDash also employs deceptive tactics, such as falsely claiming device issues to trick users into downloading additional apps.
4. Fireball (2017)
Developed by a Chinese company, Fireball infected over 250 million computers worldwide. It hijacked web browsers by changing default search engines and homepages to fake ones. It tracked user activity to display targeted ads and could install other potentially harmful software.
5. DealPly (2019)
DealPly installs as a browser extension and pretends to be a helpful shopping tool. It tracks your browsing to serve you targeted ads in search results. DealPly's persistence and hard-to-remove features are an example of how adware can really intrude on online privacy and user experience.
6. HiddenAds (2020)
This mobile adware disguises itself as a game or a tool in unofficial app stores. After installation, it hides its icon, so you can't find and uninstall it. HiddenAds serves persistent ads and consumes device resources, causing performance issues and battery drain.
Using reliable antimalware software is highly recommended for comprehensive cleanup. The best removal tools can find and delete both visible and hidden components, including any so-called “resuscitators” (files that could reinstall the adware after deletion).
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For years, Bitdefender has been fighting cybercrime. Using our deep expertise in neutralizing For organizations, Bitdefender’s GravityZone Platform offers strong, multi-layered protection against adware, focusing on prevention and detection. Through Endpoint Protection, GravityZone monitors device activity for suspicious patterns associated with adware, helping to detect and block unwanted programs before they affect performance or privacy.
Additional tools in GravityZone strengthen adware defenses. Network Attack Defense is a feature that blocks unauthorized network connections that adware might use, preventing it from downloading extra components or communicating with external servers. Since malware frequently exploits outdated software, GravityZone’s Patch Management automatically identifies and applies critical updates across your organization, closing vulnerabilities that adware might leverage.
GravityZone Web Traffic scanner can scan fragments of files as they are being downloaded and block adware from getting on systems. The included content control features also give organizations the power to block users from accessing sites that can compromise their security, such as those hosting pirated software that is usually littered with adware and malware.
For organizations with a mobile workforce, GravityZone Security for Mobile provides dedicated protection against adware and other threats targeting mobile devices. Supporting both Android and iOS, this solution continuously monitors for malicious behavior and enables remote management to ensure robust security across all endpoints, whether on desktop or mobile.
For more comprehensive oversight, Extended Detection and Response (XDR) provides visibility across endpoints, networks, cloud, and email systems, allowing early detection and removal throughout your infrastructure.
While it can invade your privacy by collecting browsing data to serve ads, adware is generally more annoying than harmful. A more serious risk is that it can act as a backdoor for more dangerous malware. Malicious actors can use it as a gateway and exploit it to install viruses, ransomware, or spyware on your device without your consent. This allows malicious malware to get in through the "innocent" face of adware and put your files, sensitive data, and system security at risk.
Other types of malware (viruses, ransomware, etc.) are inherently malicious, designed to damage files, steal info, demand ransom and so on.
Adware is not always illegal. If it’s included with software openly and users agree to it, then it usually falls within legal limits. However, when it installs itself without clear consent, is hard to remove, or tracks a user’s behavior secretly, it can be seen as invasive. In those cases, it may be considered a "potentially unwanted program" (PUP) and sometimes even illegal if it breaks privacy laws.
The legality depends on where you are, as some places have stricter rules about user consent and data privacy. But in general, adware that operates transparently and respects user choices is usually allowed.
Getting adware over and over again usually means two things. Most often, it is because permissions to install are given too quickly - by clicking through the installation screens without reading the fine print or downloading programs without checking the source. Also, it means that you don't have good security software that can block these installations before they happen.
And even when you do remove it, some variants are particularly stubborn - they create backup components that hide in your system and can reinstall themselves after you think you've removed them. These hidden elements often embed themselves in legitimate system processes and can survive regular uninstallation attempts, which is why the same symptoms keep returning.