What is ad fraud?
Ad fraud is any paid-advertising traffic that costs you money but can never become a customer. It covers fake clicks, fake impressions, fake leads, and fake conversions generated by bots, automated scripts, click farms, and competitors across search, social, and display advertising. Advertisers lose tens of billions of dollars to it every year, and knowing the main types of ad fraud, and which channels each one targets, is the first step to stopping it.
The six types of ad fraud
Ad fraud is an umbrella term. Underneath it sit six distinct attack patterns, each targeting a different part of the advertising funnel and each needing its own defence. Most advertisers only meet two or three of them in practice, depending on where they spend.
- Click fraudBots, scripts, click farms, or competitors clicking your paid ads with no intention of buying. You are billed for every click.Search, Display
- Impression fraudBots loading ads in hidden iframes or stacked, invisible placements so the advertiser is billed per impression no human ever saw.Display, programmatic, video
- Attribution fraudNetworks taking credit for conversions they did not generate, through cookie stuffing or click injection.Affiliate, mobile
- Install fraudFake mobile app installs paid for as conversions, often via device farms or SDK spoofing.Mobile user-acquisition networks
- Lead fraudBot-generated form submissions and fake call leads that fill your CRM with contacts who will never convert.All paid channels
- Brand-safety fraudAds served next to harmful, inappropriate, or counterfeit content, damaging the brand rather than the budget directly.Display, programmatic, video
Which channels ad fraud targets
Every advertising channel has its own fraud profile. Paid search is the most heavily defended and still leaks, mostly through competitor clicking and sophisticated bots that slip past the platform's own invalid-click filter. Performance Max trades transparency for automation, so fraud shows up as inflated clicks on placements you cannot see and lead-form spam the dashboard does not surface. Microsoft Advertising mirrors Google's structure at smaller scale, with a similar but lower-volume fraud profile.
Display and programmatic sit at the loose end, where impression fraud and made-for-advertising sites waste the largest share of budget. Paid social is dominated by lead-form spam and bot impressions on video placements. The practical takeaway is that the fraud you need to worry about is decided by where your money goes, not by the total size of the problem across the whole industry.
Ad fraud vs click fraud
The two terms get used interchangeably, but click fraud is only one of the six categories above. Click fraud is the paid-search and paid-social variant: someone or something clicks your ad, you pay for the click, and no buying intent was ever behind it. It is the type most SMB advertisers actually encounter, because most SMB budgets run on cost-per-click campaigns. For the full definition of the narrower term, see what is click fraud.
Ad fraud is the wider bucket that also includes impression, attribution, install, lead, and brand-safety fraud. If your spend is concentrated in Google and Microsoft search plus Performance Max, click fraud and lead fraud are the parts of the ad-fraud picture that will cost you real money, and they are the parts a tool like ClickGuardian is built to stop.
How to stop ad fraud
Stopping ad fraud comes down to scoring traffic in real time and blocking the sources that score as fraudulent before your budget moves, then reporting what was blocked so the protection can be verified. No single tool covers all six categories well, so match the defence to where you spend. For protection across your search, Performance Max, and Microsoft campaigns, see ad fraud protection, the channel-by-channel pillar guide.
For the click and lead fraud that hits paid search hardest, click fraud protection scores every visit and adds offenders to your campaign exclusion lists automatically, from $49 a month. The click fraud prevention guide walks through the techniques, and the 2026 click fraud statistics page collects the numbers behind the scale of the problem.
See your real fraud rate
Setup runs through the Google Ads or Microsoft Advertising API in about 5 minutes. Cancel anytime within the trial.