Malvertising: How to Spot, Investigate, and Prevent Malware From Ads

Quick Answer: Malvertising is the use of online ads to deliver malware or send people to scam pages. You can get malware from ads in two ways: the ad itself redirects you to a malicious page or exploits an unpatched browser, or the ad looks like a real brand and tricks you into downloading a fake installer. To protect yourself, keep your browser and operating system updated, avoid downloading software from ad links (go to the vendor's site directly), use a reputable ad and content blocker, and run security software. If you clicked a suspicious ad, close it and review what happened. If you ran a download or suspect compromise, disconnect and scan the device; if you entered credentials, change them from a clean device. Report the ad. Advertisers and publishers should vet their ad supply chain, scan creatives, and monitor for suspicious redirects and traffic.

This guide is written for defense and response. It explains how malvertising works at a conceptual level so you can recognize and block it, and it does not include instructions for building malicious ads.

What is malvertising?

Malvertising (malicious advertising) is the abuse of legitimate online advertising to spread malware or run scams. The ad can appear on a trusted website, in search results, on social media, or in an app, which is what makes it effective: the person did not visit anything risky on purpose.

It is different from adware. Adware is unwanted software already on your device that shows you ads. Malvertising uses ads as the delivery method for something harmful.

Can you really get malware from ads?

Yes, but it usually takes one of a few paths. Merely seeing an ad is rarely the problem on a fully updated device. The risk rises when you click, when the ad forces a redirect, or when your software has known, unpatched vulnerabilities.

Path	What happens	Risk factor
Fake software ad	A search or display ad imitates a well-known app and links to a look-alike download page with a bad installer	You download and run the file
Malicious redirect	The ad silently sends the browser to another page, often a scam or a fake "your device is infected" screen	Clicking, or a forced redirect on a weak ad network
Drive-by download	A page tries to exploit a flaw in an outdated browser or plug-in	Outdated software
Fake update or alert prompt	A pop-up claims you need a browser update, a codec, or a security fix	You approve or install it
Malicious QR code or app ad	An ad pushes you to a rogue app or sideloaded package	You install from outside an official store

How does malvertising get into legitimate ad networks?

Ad delivery involves many parties: advertisers, agencies, ad networks, exchanges, and publishers. Attackers exploit that complexity in a few conceptual ways:

Clean first, malicious later. A creative passes review, then its destination or code is changed after approval.
Compromised or fake advertiser accounts. Stolen or newly created accounts are used to buy placements.
Brand impersonation in search ads. Ads that copy a real brand name and display URL, but whose final destination is different.
Long supply chains. The more resellers between the advertiser and the page, the harder it is for anyone to check what is actually being served.
Cloaking. The ad shows reviewers one thing and real users another, sometimes depending on location, device, or time.

What are the warning signs of a malicious ad?

Look for these before you click, and again after the page opens:

A mismatch between the ad and the destination. The ad says one brand, but the address after the click is a different domain.
Software downloads from an ad. Legitimate vendors almost always have a normal download page you can reach by typing their address.
Urgent scare messages. Claims like "your device is infected" or "your account will be closed" shown by a website are a classic trick.
Too-good offers. Free premium software, big discounts, or prizes with unusual conditions.
A forced redirect. The page changes by itself or opens new tabs without a click.
Permission requests that make no sense. Notification prompts, installs, or admin requests right after landing.
Look-alike domains. Small spelling differences, extra words, or unusual extensions in the address.

What should you do if you clicked a malicious ad?

Do not enter anything else. Close the page. If a download started, do not open it.
Disconnect from the network if you ran or installed something, to limit data leaving the device.
Run a full scan with trusted security software, and remove anything it flags. Update the software first if you can.
Check what changed. Look at recently installed programs, browser extensions, startup items, and notification permissions, and remove anything you did not choose.
Change passwords from a different, clean device, starting with email, banking, and anything that stores payment methods. Turn on multi-factor authentication.
Watch your accounts for unfamiliar logins, charges, and forwarding rules in your email.
Consider a reset or reinstall if the device still behaves strangely. For a work device, report it to your IT or security team right away.
Report the ad to the platform where you saw it, and report the destination domain to your browser's safe-browsing reporting page.

How can you protect yourself from malware in ads?

Keep everything updated. Browser, operating system, and extensions. Patched software closes the holes drive-by attacks depend on.
Install software only from the vendor's site or an official store. Type the address or use a bookmark instead of clicking an ad.
Use an ad or content blocker from a reputable provider, and keep it updated.
Use security software with web protection.
Be skeptical of search ads for downloads and logins. Scroll to the organic result or use a saved link.
Use a password manager. It will not auto-fill on a look-alike domain, which is a useful warning.
Limit extensions and admin rights. Fewer extensions means a smaller attack surface, and a standard user account limits what a bad installer can change.

How can advertisers and publishers reduce malvertising risk?

Malvertising hurts advertisers (brand damage, wasted spend, impersonation) and publishers (infected visitors, lost trust). Practical steps:

For publishers

Work with ad partners that scan creatives and enforce quality standards.
Publish and maintain ads.txt so only authorized sellers can sell your inventory.
Use content security policies and sandbox ad iframes where possible.
Block known bad domains and redirect behavior, and give users an easy way to report ads.
Monitor for forced redirects and unusual traffic drops, which can signal a bad ad.

For advertisers

Monitor search results and social ads for impersonation of your brand, and report them quickly.
Keep control of your ad accounts: strong passwords, multi-factor authentication, and limited access.
Use allowlists for important placements, and review placement reports for unfamiliar domains.
Check your landing pages and tracking links regularly, so no one can swap them without you noticing.
Compare ad clicks with real sessions and conversions. Traffic that clicks but never engages can point to bots or low-quality sources.
Document and dispute bad placements with your platform and partners.

Malvertising vs. adware vs. click fraud: what is the difference?

Term	What it is	Who is the target
Malvertising	Ads used to deliver malware or scams	Viewers, and brands whose names are abused
Adware	Unwanted software that shows ads on a device	Device owners
Click fraud	Fake or invalid clicks that drain ad budgets	Advertisers

They overlap in practice. The same low-quality or compromised supply chain can serve malicious ads to people and fake traffic to advertisers.

Common mistakes

Downloading software from the first ad in a search result.
Trusting a page because it uses HTTPS or looks professional.
Delaying browser and system updates.
Not changing passwords after a suspected infection, or changing them on the same infected device.
Advertisers who never search for their own brand to see who is impersonating them.
Reviewing only the ad creative and not the final landing page and redirect path.

Quick checklist

Browser, OS, and extensions are up to date
Reputable ad blocker and security software installed
Software downloaded only from official sites or stores
Password manager and multi-factor authentication in use
(Advertisers) Brand impersonation checks scheduled
(Advertisers) Placement and landing page reviews in place
(Publishers) ads.txt current and redirect monitoring on
A clear process for reporting suspicious ads

FAQ

What is malvertising in simple terms?

It is the use of online ads to spread malware or trick people into scams. The ad may look normal and appear on a trusted site.

Can I get a virus just by seeing an ad?

It is uncommon on an up-to-date device, but possible if the ad exploits an unpatched flaw. Most infections involve a click, a download, or approving a prompt.

How do I know if an ad is dangerous?

Check whether the destination matches the brand, whether it pushes a software download, and whether it uses scare messages or forced redirects. When unsure, do not click. Go to the company's site by typing the address.

Are ads on Google and social media safe?

Platforms review ads, but impersonation and cloaking still occasionally get through. Treat ads for software downloads, logins, and support numbers with extra caution.

Do ad blockers prevent malware from ads?

They reduce exposure because many malicious ads never load. They are not a complete defense, so pair them with updates and security software.

What should I do if I downloaded a file from an ad?

Do not open it. If you already ran it, disconnect from the network, run a full security scan, check for new programs and extensions, and change your passwords from a clean device.

Is malvertising the same as adware?

No. Adware is software on your device that shows ads. Malvertising is the use of ads to deliver malware or scams.

How can businesses tell if their ads are being abused?

Search for your brand regularly, review placement and referral reports for unknown domains, monitor landing pages for unexpected changes, and compare click data with real engagement. Report impersonating ads to the platform and use takedown channels for the destination domains.

Can malvertising affect my ad spend?

Yes. Low-quality supply chains that carry malicious ads also tend to carry fake traffic. Clicks from bots or bad placements cost money without producing customers.

Next Steps

Malware from ads is real but preventable. For individuals, the biggest wins are updated software, downloads only from official sources, and a healthy distrust of ads that ask for installs or scare you. For businesses, the fix is visibility: know where your ads run, who can sell your inventory, and whether your clicks turn into real visits.

Investigate redirects separately from fake and invalid traffic. Our website bot attack guide covers additional site-level checks.

Investigate Your Paid-Click Quality

JuicyTraffic helps advertisers investigate landing-page click quality by campaign, source and placement using a tracking link and an on-site probe. Compare its per-click evidence with ad-platform reports and business outcomes. It does not replace malware protection, a website firewall, impression verification or an A/B testing platform.

About the Author

Dylan Dan is the founder of JuicyTraffic. He has spent 15 years specializing in adult advertising and ad-fraud prevention, helping advertisers assess traffic quality, identify invalid clicks and protect media budgets across dedicated ad networks.