What is malvertising?
Malvertising is advertising used as a weapon. The ad looks ordinary, but it leads to, or quietly loads, something harmful. The common forms are:
- Fake download buttons that install unwanted or malicious software instead of the program you wanted.
- Scam pages: fake virus warnings, “your PC is infected” pop-ups with a phone number to call, prize and gift-card scams.
- Forced redirects that take you from the page you were reading to a scam or phishing site without a click.
- Impersonation ads that copy a real brand and lead to a look-alike site built to steal a login or a card number.
Why do malicious ads appear on trustworthy sites?
Because most sites do not choose the ads they show. The space is sold in an automatic auction that runs in the moment a page loads, through ad networks that resell to other networks. A criminal who gets a bad ad into that chain can have it shown on news sites, forums and search results alike, often only briefly and only to some visitors, which makes it hard for the site to catch.
What does the FBI recommend?
In December 2022 the FBI warned that criminals were buying search-engine ads that impersonate real brands, leading to look-alike sites that install ransomware or steal logins and financial details. Among its advice to the public: use an ad blocker when searching the internet, and check a link’s address before clicking an ad. The warning is FBI public service announcement I-122122-PSA. That is general advice about ad blockers, not about AdFender in particular. The point stands well beyond search: malicious ads reach people through the same channels as every other ad.
How does AdFender keep malicious ads away?
AdFender blocks ads before they load, so malicious ads served from the ad networks on its lists never reach your browser. Its ad-blocking and anti-tracking lists are on from the start and name the ad servers and networks to refuse. When a page asks for something from one of them, the request is never made: nothing downloads, no script runs, and any redirect that ad would have triggered never happens.
- Your browsers, one install. The protection covers Chrome, Edge, Firefox, Opera and other supported browsers on your PC, not just the one with an extension in it, plus other desktop programs you add.
- Inside secure pages. Nearly every ad arrives over HTTPS. With HTTPS filtering on, AdFender can block an individual ad script, not just a whole ad server.
- Kept current for you. The lists are maintained continuously as new ad networks and scam domains appear, and AdFender updates them on its own.
How can you see it working?
Turn on the Activity log in AdFender and open a busy, ad-supported page. Each blocked request is listed live, with the list and the rule that blocked it. The dashboard keeps a running count of ads and trackers blocked.
What does an ad blocker not protect you from?
An ad blocker cuts off one delivery route. It is not antivirus, and it does not replace the security software already on your PC. It cannot stop a harmful file you download on purpose, a phishing link in an email, or a scam site you go to directly. A brand-new ad network can get through until the lists catch up with it, and ads a site serves from its own servers, including the sponsored results some search engines show, are harder to remove than ads from an ad network. So check the address before you click a sponsored result. Use an ad blocker alongside your security software, not instead of it.
Related: AdFender also blocks the trackers that ride along with ads, covered in how to stop websites tracking you. If ads still get through on a site, ads are still showing finds the cause.