Red Hat Jolokia: incomplete denylist

A flaw was found in Jolokia's JSR-160 proxy functionality where insufficient validation of client-controlled JMX service URLs allows a bypass of the denylist introduced to mitigate CVE-2018-1000130. The proxy accepts a target.url value from a Jolokia POST request and passes it to JMXServiceURL and JMXConnectorFactory for establishing the remote JMX connection. The existing denylist only rejects URLs matching service:jmx:rmi:///jndi/ldap:.*, which can be bypassed using alternative valid JMX service URL forms, including ldaps:// schemes or LDAP URLs with a non-empty JMX host component. These URLs are accepted as valid JMXServiceURL objects and can cause the Jolokia agent JVM to perform a JNDI lookup against an attacker-controlled LDAP endpoint. This can result in server-side request forgery (SSRF), forwarding of supplied JMX credentials to the remote endpoint, and potentially remote code execution depending on the classes and configuration available in the target JVM.