What is Adware and How To Remove It

Bart Lenaerts-Bergmans - May 8, 2023

What Is Adware?

Adware — or advertising-supported software — is automated, unwanted software designed to monitor online user behavior and bombard them with targeted advertisements, banners and pop-ups.

Problems with adware mostly happen within computers, but it ’s not uncommon for adware programs to make their way onto mobile devices.

How Does Adware Get Onto Your Device?

Adware typically infects devices via downloadable content – like any shareware or freeware – that opens the door to malicious third-party programs. These can covertly install ad software onto your device without your knowledge.

Program developers can make money each time an ad is displayed or clicked on, meaning even legitimate companies can be tempted to include adware in their software.

Signs of an Adware Infection

How do I know if I have adware on my device?

Spotting adware shouldn’t be too difficult because it will naturally reveal itself by design. Your device may be infected with adware if:

  • You’re experiencing significant dips in speed and performance
  • You become inundated with pop-up ads – even if you’re not browsing the internet
  • You’re being sent ransom demands or warnings from unknown apps with urgent warnings
  • You’re experiencing reduced functionality (sometimes adware hinders access to your tools and device settings)
  • You notice the sudden appearance of new browser add-ons and toolbars – likely without your permission
  • You find your devices keep crashing

Mobile Malware Signs

Smartphones often share similar problems when infected. Adware is likely the culprit if:

  • Your phone is slow to load apps or perform usual tasks
  • Your battery drains rapidly
  • Data usage bills are unexpectedly high at the end of the month
  • Numerous ad pop-ups and new tabs open on your smartphone

Expert Tip

Only download software from secure, trusted websites and make sure to have the latest antivirus software in place to prevent adware malware from infecting your system.

Is Adware a Virus?

While technically not a virusand sometimes even helpful, legitimate and legaladware can still cause problems for victims. Not only can the wrong types of adware eat up all your processing power and data – slowing down your system until it’s virtually unusable – but it can be a gateway to other forms of malware and man-in-the-middle attacks.

Typically, adware malware isn’t as damaging as trojans, worms, rootkits, and ransomware and is often no more than a nuisance. However, some adware can be used for invasive spying, data collection and monitoring that can be extremely harmful to victims.

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Adware Tracking Cookies

Cookies record data on users who visit the site – like their settings, session time and any data entered on forms – while also generating a unique number for your device to store useful information for you. Tracking cookies are simply a small text file that websites send to users’ web browsers to track their behavior online. They are designed to improve the user experience online by remembering login details, saving viewed items and adding them to shopping carts and even offering tailored advertisements.

However, cookies can also be used maliciously in the form of adware tracking cookies. Because all cookies store personal data, malicious adware tracking cookies can access sensitive data innocuously and use it to your detriment – with adware authors often even selling your data to other malicious actors.

Types of Adware

Despite its often-unwanted nature, not all adware is illegal – and if anything, it’s far more common than you might expect.

1. Traditional Legal Adware

Traditional legal adware is a profitable business model. Pay-per-click, pay-per-view and pay-per-install adware models are even used by reputable firms to market products and promote free software. However, the legality lies in consent – users must know what they’re downloading. Without consent, adware becomes problematic.

2. Potentially Unwanted Programs (PUPs)

PUPs are types of adware that reside in your device without your knowledge or desire, even if you’ve given consent for their download. While they may not necessarily be malicious, PUPs can provide a platform for further malware to make its way onto your device – making it a notoriously gray area in terms of legality.

3. Malicious Adware

Malicious Adware PUPs are the most damaging. Distributors aim to cause as much damage as possible to their targets, with their adware campaigns usually involving embedding harmful ransomware or trojans inside the adware.

This adware may target your browser and clog up your screens with toolbars and advertisements. These toolbars may even contain trojans that redirect your searches away from legitimate sites, towards fraudulent replicas designed to look like carbon copies of the original – so, take extra care when browsing and always double-check URLs when entering new sites.

How To Remove Adware on a PC

When it comes to adware, prevention is the best cure. However, mistakes can happen and understanding how to remove adware on your PC can make your life a lot easier and your data safer.

Firstly, adware usually embeds itself in a file that has been downloaded with or without your permission – whether maliciously embedded with rootkits or simply in your saved files.

To remove adware manually, Windows users should:

  • Close all running software and any open browsers
  • Open “Windows Task Manager”
  • Select “Processes” to see a list of files currently running
  • Look for any suspicious files running in the background, right-click and select “End Task”
  • Go to your personal “Control Panel” and click “Uninstall Program”
  • Highlight any programs you suspect to be problematic and delete them

However, this may not be enough to completely remove the threat if the adware has resuscitation capabilities built-in – which revive the software even after it has been removed.

It’s important to also conduct a comprehensive scan of your system with antivirus software. This locates problematic files and eliminates any trace of them. Make sure to check that your anti-malware software has adware blocker capabilities and that these settings are turned on before scanning.

How To Remove Adware on Android

Once adware takes hold, it can seriously affect the performance of your phone. To clean your Android smartphone of any adware, you should do the following:

  • Stop all applications currently running in the background and close all open browser pages
  • Open your settings and access your application manager
  • Select the “Running” tab and “Force Stop” all running applications
  • Highlight any recent or unrecognized apps or files from your phone, tap the “clear cache” and “clear data” buttons and finally uninstall them

You’ll need to clear your browser history too. To do this, simply:

  • Go into the browser (Internet Explorer, Google Chrome, Mozilla Firefox etc.) and tap the ‘Options’ button
  • Select “Settings” and head to the “Privacy and Security” section
  • Here you can clear your cache data and delete your browsing history

After you’ve done this, it’s good to restart the device and install antivirus software for added peace of mind.

How To Remove Adware on iPhone

Removing adware from an iPhone is just as simple as on any other device — it just takes slightly different steps. To do this, you need to:

  • Update to the latest iOS before you get into removing any adware or malware and restart your device
  • Tap “Settings” and then “General”
  • Select “Clear History and Website Data” and confirm
  • Remove any suspicious or untrustworthy apps from your phone, too, to prevent the return of any adware

5 Adware Prevention Best Practices

At best, adware and associated pop-ups are annoying — at their worst, they can cripple your device. As with most cybersecurity risks, prevention is the best defense against adware.

To prevent adware, spyware and other harmful malware infecting your PC and other devices, you should overall practice safe browsing. To do so:

  1. Install an Adware Blocker: These stop your browser from automatically downloading advertisements and other pop-up content, protecting your browser against adware and the harmful viruses that can accompany it.
  2. Update Your Antivirus Software: Cybercriminals rely on you falling into bad habits online, like clicking on malicious links, not updating your security software or simply not having any in the first place. New updates protect against novel strains of malware and the latest tactics used by cybercriminals.
  3. Consider Which Advertisements You’re Clicking: Think twice before clicking advertisement links or downloading files online. Make sure URLs match the linked anchor text and that you’re only accessing safe SSL-certified sites — indicated with “HTTPS” at the beginning of the site address. Secure web pages are also marked with a padlock symbol.
  4. Enable Incognito Mode: Although incognito mode doesn’t stop malware from infecting a device, it does prevent your browser from storing cookies. As cookies accumulate, your device begins to slow and the chance of harboring malicious adware tracking cookies increases.
  5. Clear Your Cache and Cookies: Minimize the impact of potentially malicious cookies by regularly clearing your browser cache. This helps prevent tracking adware cookies from following you around the web.

Learn More

Learn about CrowdStrike’s next-generation antivirus, Falcon Prevent, and how it can help you defend your business against advanced threats with world-class AI and adversary-focused intelligence. Learn More: Falcon Prevent NGAV


Bart is Senior Product Marketing Manager of Threat Intelligence at CrowdStrike and holds +20 years of experience in threat monitoring, detection and intelligence. After starting his career as a network security operations analyst at a Belgian financial organization, Bart moved to the US East Coast to join multiple cybersecurity companies including 3Com/Tippingpoint, RSA Security, Symantec, McAfee, Venafi and FireEye-Mandiant, holding both product management, as well as product marketing roles.