Executive brief
Fides is an open-source privacy and data governance platform used to manage customer data requests and compliance. A timing-based username enumeration vulnerability allows attackers without authentication to discover valid usernames by measuring how long the login endpoint takes to respond—valid usernames trigger longer response times than invalid ones. An attacker can use this information to build a list of real usernames and then conduct password brute-force or credential-stuffing attacks against those accounts.
Technical details
The vulnerability is a timing attack on the authentication endpoint (/api/v1/login) caused by inconsistent processing time between valid and invalid username lookups. An unauthenticated attacker can send repeated login requests with various usernames and measure response times using tools like curl; valid usernames exhibit measurably longer server-side processing time (average ~0.68 seconds) compared to invalid usernames (~0.19 seconds), enabling systematic username enumeration. The root cause is likely that valid username checks perform additional operations (e.g., password hashing/validation) before rejecting the request, while invalid usernames fail faster. The vulnerability has been patched in Fides version 2.44.0; users running versions below 2.44.0 should upgrade immediately.
Affected products
- Ethyca Fides < 2.44.0
Timeline
- 2024-09-04: disclosed
- 2024-09-04: patched: Patched in version 2.44.0