Tech companies have repeatedly reassured the public that trackers used to follow smartphone users through apps are anonymous or at least pseudonymous, not directly identifying the person using the phone. But what they don’t mention is that an entire overlooked industry exists to purposefully and explicitly shatter that anonymity.
They do this by linking mobile advertising IDs (MAIDs) collected by apps to a person’s full name, physical address, and other personal identifiable information (PII). Motherboard confirmed this by posing as a potential customer to a company that offers linking MAIDs to PII.
“If shady data brokers are selling this information, it makes a mockery of advertisers’ claims that the truckloads of data about Americans that they collect and sell is anonymous,” Senator Ron Wyden told Motherboard in a statement.
“We have one of the largest repositories of current, fresh MAIDS<>PII in the USA,” Brad Mack, CEO of data broker BIGDBM told us when we asked about the capabilities of the product while posing as a customer. “All BIGDBM USA data assets are connected to each other,” Mack added, explaining that MAIDs are linked to full name, physical address, and their phone, email address, and IP address if available. The dataset also includes other information, “too numerous to list here,” Mack wrote.
A MAID is a unique identifier a phone’s operating system gives to its users’ individual device. For Apple, that is the IDFA, which Apple has recently moved to largely phase out. For Google, that is the AAID, or Android Advertising ID. Apps often grab a user’s MAID and provide that to a host of third parties. In one leaked dataset from a location tracking firm called Predicio previously obtained by Motherboard, the data included users of a Muslim prayer app’s precise locations. That data was somewhat pseudonymized, because it didn’t contain the specific users’ name, but it did contain their MAID. Because of firms like BIGDBM, another company that buys the sort of data Predicio had could take that or similar data and attempt to unmask the people in the dataset simply by paying a fee.
“This real-world research proves that the current ad tech bid stream, which reveals mobile IDs within them, is a pseudonymous data flow, and therefore not-compliant with GDPR,” Edwards told Motherboard in an online chat.
“It’s an anonymous identifier, but has been used extensively to report on user behaviour and enable marketing techniques like remarketing,” a post on the website of the Internet Advertising Bureau, a trade group for the ad tech industry, reads, referring to MAIDs.
In April Apple launched iOS 14.5, which introduced sweeping changes to how apps can track phone users by making each app explicitly ask for permission to track them. That move has resulted in a dramatic dip in the amount of data available to third parties, with just 4 percent of U.S. users opting-in. Google said it plans to implement a similar opt-in measure broadly across the Android ecosystem in early 2022.