Search Guard Kibana Plugin versions before 5.6.8-7 and before 6.x.y-12 had an issue that an authenticated Kibana user could impersonate as kibanaserver user when providing wrong credentials when all of the following conditions a-c are true: a) Kibana is configured to use Single-Sign-On as authentication method, one of Kerberos, JWT, Proxy, Client certificate. b) The kibanaserver user is configured to use HTTP Basic as the authentication method. c) Search Guard is configured to use an SSO authentication domain and HTTP Basic at the same time
CWE-287 - Improper Authentication
Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.