Apple has warned developers they must disclose the use of screen recording software or face "immediate action".
The company has responded after reports of major travel apps using session replay technology to recode iPhone users' screens without getting proper consent.
In a statement, an Apple spokesperson told TechCrunch: "Protecting user privacy is paramount in the Apple ecosystem.
"Our App Store Review Guidelines require that apps request explicit user consent and provide a clear visual indication when recording, logging, or otherwise making a record of user activity.
"We have notified the developers that are in violation of these strict privacy terms and guidelines, and will take immediate action if necessary."
Analytics firm Glassbox is being used to embed cod in a mobile app to record user activity, and while there is no indication that it is misusing any data, there is an issue with travel and hotel companies failing to disclose the technology to users.
Air Canada's mobile app has been found to fail to mask sensitive user data, raising concerns over the fact that neither that company nor the likes of Expedia, Hotels.com and Abercrombie & Fitch have been open with customers.
Responding to the controversy, Glassbox said: "Glassbox and its customers are not interested in 'spying' on consumers. Our goals are to improve online customer experiences and to protect consumers from a compliance perspective.
"Since its inception, Glassbox has helped organizations improve millions of customer experiences by providing tools that record and analyze user activity on web sites and apps.
"This information helps companies better understand how consumers are using their services, and where and why they are struggling.
"We are strong supporters of user privacy and security. Glassbox provides its customers with the tools to mask every element of personal data.
"We firmly believe that our customers should have clear policies in place so that consumers are aware that their data is being recorded -- just as contact centers inform users that their calls are being recorded."