CVE-2024-55374

Step 1: Initial Probe: The attacker sends a login request with a known or guessed username and password to the REDCap login endpoint.

Step 2: Response Analysis: The attacker observes the response from the server. This could involve analyzing response times, error messages, or HTTP status codes.

Step 3: Username Iteration: The attacker iterates through a list of potential usernames, sending login requests for each.

Step 4: Differentiation: The attacker compares the responses received for each username. Valid usernames will exhibit a different response (e.g., slightly longer response time, different error message) compared to invalid usernames.

Step 5: Username Identification: The attacker identifies valid usernames based on the observed discrepancies.

Step 6: Further Exploitation (Optional): Once valid usernames are identified, the attacker can attempt password guessing, brute-force attacks, or other attacks targeting those accounts.

The vulnerability stems from an inconsistent response time or error message differentiation between valid and invalid username attempts. Specifically, the application likely provides slightly different feedback (e.g., response time, error message) depending on whether the entered username exists in the system. An attacker can leverage this observable difference to systematically probe the system with various usernames. The root cause is a lack of proper rate limiting or consistent error handling for login attempts, allowing attackers to differentiate between valid and invalid usernames. This flaw doesn't directly involve a buffer overflow or SQL injection, but rather a timing-based side-channel attack. The application's design fails to adequately obscure the presence or absence of a user account, making it susceptible to enumeration.