Surveillance Companies Track Mobiles Using Advertising Data

Published on January 22, 2026 | Translated from Spanish
Infographic showing how a mobile phone's advertising identifiers (IDFA and GAID) are combined with location data and app data to create a user profile that is monitored by surveillance companies' servers.

Surveillance Companies Track Mobiles Using Advertising Data

A Le Monde report exposes how firms dedicated to monitoring people use information from the online advertising system to track smartphone users. 🕵️‍♂️ These organizations collect and link advertising identifiers, geolocation details, and application information, thereby building comprehensive individual profiles. This process often occurs without transparent consent, taking advantage of the intricate digital advertising supply chain.

Surveillance companies track mobiles using advertising data

Advertising Data Turns into a Tracking Tool

The mechanism is based on Apple's IDFA and Google's GAID, created to be anonymous and resettable by the user. However, surveillance companies merge them with other more permanent data, such as IP addresses or usage habits, to re-identify people. This transforms a tool for measuring campaign effectiveness into a continuous tracking system, often marketed to public administrations or corporations. 🔄

Key elements that enable this tracking:
  • Advertising identifiers (IDFA/GAID): Although resettable, they are used as a starting point.
  • Persistent data: Such as IP or behavior patterns, which allow re-identification.
  • Opaque supply chain: The complexity of the market makes it hard to know where the information ends up.
Tracking technology evolves faster than the laws trying to regulate it.

The Fragmented Market Enables Large-Scale Surveillance

The fragmentation in the online advertising sector, with thousands of intermediaries, complicates controlling the final destination of the information. A SDK integrated in a flashlight app or an ad in a game may be transmitting data to these companies' servers. Regulations like the GDPR in Europe seek to restrict these actions, but compliance is uneven and technical methods advance faster than legislation. ⚖️

Factors contributing to mass monitoring:
  • Market fragmentation: Thousands of players in the digital advertising chain.
  • Access via simple apps: Apparently innocuous software (like flashlight apps) can host tracking SDKs.
  • Regulatory lag: Privacy laws fail to keep up with new surveillance techniques.

Final Reflection for the User

Therefore, the next time a free app requests permission to personalize ads, consider that the profile generated with your data could end up in a dossier for any entity willing to pay for it. The thin line between targeted advertising and covert surveillance blurs in this ecosystem. 🛡️