Protect Your Privacy: How to Prevent Your Phone from Sharing Data Without Your Knowledge

If you keep your smartphone on standby on your nightstand instead of turning it off at night, you should be aware of the potential data transmission happening without your knowledge.

While some data transfer is essential for device maintenance, such as security patches or system updates, there is also unnecessary data being sent.

Marijus Briedis, CTO of NordVPN, informed TechRadar that smartphones transmit signals related to tracking or advertising, including personal data that should not be shared without explicit consent.

What your phone does at night

Your phone is not just recharging like you are.

The data transmitted by a smartphone can be categorized into legitimate data for device functionality and sensitive data used for tracking, advertising, and other purposes.

Distinguishing between these types of data can be challenging. For instance, diagnostic data sent to manufacturers or app developers may be necessary but usually requires user consent.

Moreover, smartphones transmit various information, including location, device IDs, usage patterns, and other data that are aggregated to create detailed profiles for targeted advertising with higher success rates.

Reports from 2025 revealed that Android users were specifically monitored by major companies like Meta and Yandex. There have been indications for a while that smartphones are “listening in” and displaying tailored ads based on user conversations.

Despite these practices, there have been minimal consequences. Many smartphones still operate this way, but there are methods to limit data sharing.

How to enhance your protection

To reduce background data sharing, review the permissions of your installed apps.

Apps with access to location, microphone, camera, and tracking data pose risks. Only grant permission for these functions while actively using the apps (be cautious with apps running continuously in the background).

Go to Settings > Security & Privacy > Permission Manager (or equivalent).

Jon Mundy / Foundry

Additionally, you can disable background refresh on both iOS and Android to limit automatic cloud backup synchronization. Evaluate the necessity of this feature based on its benefits and drawbacks.

It is recommended to disable personalized ads. On Android devices, navigate to Google Services > All Services > Advertising to access this setting and reset your advertising ID.

Using a VPN service can offer added protection against tracking and data sharing.

If you are concerned about data sharing, especially at night, consider turning off your phone entirely (a good practice) or activating flight mode.

This content was originally published on PC-WELT and has been translated and adapted from German.