UPDATE: Apple has removed the iOS app in question from the App Store.

TikTok kids, take note! Some of the most popular accounts on your favorite short-form video app may be promoting scammy Android or iOS apps designed to show ads and take your money.

This was discovered by a 12-year-old girl in the Czech Republic, who immediately reported the discovery to security firm Avast. Avast reported the details in a blog post today (September 22).

"In total, the app has been downloaded more than 2,400,000 times and has generated more than $500,000 from the people and persons behind the scam," avast said in a press release.

As of this writing, all seven of the scam apps are still available on the Google Play Store and the Apple App Store.

These apps offer wallpapers, download music, and claim to be a phone vibration game called "Shock your friends." However, they display ads on the outside of the app and charge $2 to $10 for normally free items such as wallpaper.

"The apps we found are fraudulent and violate Google and Apple's app policies by making misleading claims about the app's functionality, displaying ads outside the app, and hiding the original app icon immediately after the app is installed Avast threat analyst Jakub Vavra said.

"It is particularly problematic that apps are promoted on social media platforms popular with young children, who may not be aware of some of the red flags associated with apps and may fall for them. [Under the usernames 7odestar, Dejavuuu.es3, and Marina90lazina, avast found at least three TikTok accounts that were actively promoting the app. The first account had over 300,000 followers.

We also found one Instagram account with the username Shockmyfriends.app promoting the app; all four were still active as of Wednesday morning in New York City.

Avast said it had reported these apps and accounts to Apple, Google, Instagram, and TikTok.

There are three Android apps and four iOS apps listed by avast. As of Tuesday morning (September 22) when this article was written (Eastern time), all apps were still available for download.

Update: By Tuesday evening, the iOS ones had been removed.

To protect yourself from scam apps, be wary of those promoted on social media platforms, text messages, and instant messages.

Also, read app store reviews before downloading an app.

If you are using an Android phone, you should also install and run some of the best Android anti-virus apps. They won't catch all scam software, but they will protect you from the most dangerous ones. (Unfortunately, there is no antivirus app for iOS.)

"We thank the girl who reported the TikTok profile. Her awareness and responsible behavior is a commitment we should all show to make the cyber world a safer place."