Simon Willison’s Weblog

18th March 2024

900 Sites, 125 million accounts, 1 vulnerability (via) Google’s Firebase development platform encourages building applications (mobile an web) which talk directly to the underlying data store, reading and writing from “collections” with access protected by Firebase Security Rules.

Unsurprisingly, a lot of development teams make mistakes with these.

This post describes how a security research team built a scanner that found over 124 million unprotected records across 900 different applications, including huge amounts of PII: 106 million email addresses, 20 million passwords (many in plaintext) and 27 million instances of “Bank details, invoices, etc”.

Most worrying of all, only 24% of the site owners they contacted shipped a fix for the misconfiguration.