WSO2 WSO2 Carbon Abstract OTP Authenticator vulnerabilities

The authentication endpoint of WSO2 Identity Server fails to provide a consistent system response when a username does not exist in the system, allowing attackers to differentiate between valid and invalid usernames. This difference in responses can be leveraged to enumerate existing user accounts. Successful exploitation enables an attacker to discover valid usernames within the system, significantly increasing the risk of subsequent attacks such as brute force attacks on user credentials, social engineering attacks, and information leakage. The discovered usernames can be used to craft targeted phishing emails or other social engineering campaigns.

The system accepts authentication requests without sufficient validation to enforce tenant isolation when using Email OTP, SMS OTP, or Magic Link as first-factor authenticators. This failure to adequately separate user data between tenants can lead to the exposure of personally identifiable information. Successful exploitation allows an attacker to disclose personally identifiable information of users in different tenants, resulting in privacy violations and potential regulatory non-compliance. This may include unauthorized access to user details such as mobile numbers.