It was found that keycloak before 3.4.2 final would permit misuse of a client-side /etc/hosts entry to spoof a URL in a password reset request. An attacker could use this flaw to craft a malicious password reset request and gain a valid reset token, leading to information disclosure or further attacks.
Weakness
The product is composed of a server that relies on the client to implement a mechanism that is intended to protect the server.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Keycloak |
Keycloak |
* |
3.4.2 (excluding) |
Potential Mitigations
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Even though client-side checks provide minimal benefits with respect to server-side security, they are still useful. First, they can support intrusion detection. If the server receives input that should have been rejected by the client, then it may be an indication of an attack. Second, client-side error-checking can provide helpful feedback to the user about the expectations for valid input. Third, there may be a reduction in server-side processing time for accidental input errors, although this is typically a small savings.
References