In CVE-2023-25194, we announced the RCE/Denial of service attack via SASL JAAS JndiLoginModule configuration in Kafka Connect API. But not only Kafka Connect API is vulnerable to this attack, the Apache Kafka brokers also have this vulnerability. To exploit this vulnerability, the attacker needs to be able to connect to the Kafka cluster and have the AlterConfigs permission on the cluster resource.
Since Apache Kafka 3.4.0, we have added a system property (-Dorg.apache.kafka.disallowed.login.modules) to disable the problematic login modules usage in SASL JAAS configuration. Also by default com.sun.security.auth.module.JndiLoginModule is disabled in Apache Kafka 3.4.0, and com.sun.security.auth.module.JndiLoginModule,com.sun.security.auth.module.LdapLoginModule is disabled by default in in Apache Kafka 3.9.1/4.0.0
The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
It is often convenient to serialize objects for communication or to save them for later use. However, deserialized data or code can often be modified without using the provided accessor functions if it does not use cryptography to protect itself. Furthermore, any cryptography would still be client-side security – which is a dangerous security assumption. Data that is untrusted can not be trusted to be well-formed. When developers place no restrictions on “gadget chains,” or series of instances and method invocations that can self-execute during the deserialization process (i.e., before the object is returned to the caller), it is sometimes possible for attackers to leverage them to perform unauthorized actions, like generating a shell.