Applications that trick users into paying huge subscription fees raked in over $400 million from the Apple App Store and Google Play Store, according to research done by Avast.

The so-called “fleeceware” takes advantage of a weakness in both app stores: deleting an application tied to a subscription doesn’t cancel the subscription.

A cyber-security firm in the United Kingdom has identified 32 iOS apps that it dubs “fleeceware” for subscriptions and in-app fees that amount to a form of online fraud.

More than 3.5 million iOS users installed the apps, most of which were image editors, QR and barcode scanners, horoscope and fortune-telling apps and face filters for selfies. Two astrology apps making the list are among the first 20 in top-grossing iPhone apps in the UK.