Apple has aired its displeasure over the assertion that the company’s concern on sideloading apps into phones was exaggerated.

According to Apple, sideloading, the act of downloading apps without using an app store is dangerous.

In the letter written to members of the U.S. Senate Judiciary Committee, Apple noted computer security expert Bruce Schneier’s reaction to its concerns.

Apple acknowledged Schneier’s position that state-sponsored attackers could get through smartphones’ security controls. The company however stated that through its careful evaluation, such attacks are a “rare threat.”

Defending its stance against sideloading, Apple explained that its review of apps that are put into the App Store “creates a high barrier against the most common scams used to distribute malware.”

Sideloading is one of the positions being considered by Congress in a bill that aims at curtailing the powers of top tech companies and increasing competition.