Facebook is facing another embarrassment for once again violating user privacy, this time from one of its apps being sold on the Apple App Store.

Apple officials confronted Facebook last week for violating the company’s regulations about apps collecting user data. The app owned by Facebook, Onavo Protect, was acquired when they bought the Israeli security app developer Onavo in 2013. It provides a VPN (virtual private network), a technology that is supposed to provide privacy protection while browsing and downloading apps. Instead of providing privacy, the app was collecting lists of apps that users had installed on their phone, learning how they were being used, and sending the information to Facebook.

An Apple spokesman said in an email to CNBC, “We work hard to protect user privacy and data security throughout the Apple ecosystem. With the latest update to our guidelines, we made it explicitly clear that apps should not collect information about which other apps are installed on a user’s device for the purposes of analytics or advertising/marketing and must make it clear what user data will be collected and how it will be used.”

Facebook has been offering the app without clearly disclosing that it is the owner. Facebook had earlier told Congress that it does not use Onavo data for Facebook product uses or to collect information about individuals. But it admitted that it uses Onavo to collect a wide range of information about the apps and how they are used in order to improve its own products.

Facebook responded to the ban: “We’ve always been clear when people download Onavo about the information that is collected and how it is used. As a developer on Apple’s platform, we follow the rules they’ve put in place.”