Over 4000 Android Apps Expose Users’ Data via Misconfigured Firebase Databases

More than 4,000 Android apps that use Google’s cloud-hosted Firebase databases are ‘unknowingly’ leaking sensitive information on their users, including their email addresses, usernames, passwords, phone numbers, full names, chat messages and location data.

The investigation, led by Bob Diachenko from Security Discovery in partnership with Comparitech, is the result of an analysis of 15,735 Android apps, which comprise about 18 percent of all apps on Google Play store.

“4.8 percent of mobile apps using Google Firebase to store user data are not properly secured, allowing anyone to access databases containing users’ personal information, access tokens, and other data without a password or any other authentication,” Comparitech said.

Acquired by Google in 2014, Firebase is a popular mobile application development platform that offers a variety of tools to help third-party app developers build apps, securely store app data and files, fix issues, and even engage with users via in-app messaging features.

With the vulnerable apps in question — mostly spanning games, education, entertainment, and business categories — installed 4.22 billion times by Android users, Comparitech said: “the chances are high that an Android user’s privacy has been compromised by at least one app.”

Given that Firebase is a cross-platform tool, the researchers also warned that the misconfigurations are likely to impact iOS and web apps as well.

The full contents of the database, spanning across 4,282 apps, included:

• Email addresses: 7,000,000+
• Usernames: 4,400,000+
• Passwords: 1,000,000+
• Phone numbers: 5,300,000+
• Full names: 18,300,000+
• Chat messages: 6,800,000+
• GPS data: 6,200,000+
• IP addresses: 156,000+
• Street addresses: 560,000+

Diachenko found the exposed databases using known Firebase’s REST API that’s used to access data stored on unprotected instances, retrieved in JSON format, by simply suffixing “/.json” to a database URL (e.g. “https://~project_id~.firebaseio.com/.json”).