Deserialization of Untrusted Data
A possible security vulnerability has been identified in Apache Kafka Connect. This requires access to a Kafka Connect worker, and the ability to create/modify connectors on it with an arbitrary Kafka client, SASL JAAS config and a SASL-based security protocol, which has been possible on Kafka Connect clusters since Apache Kafka 2.3.0-rc1. When configuring the connector via the Kafka Connect REST API, an authenticated operator can set the "sasl.jaas.config" property for any of the connector's Kafka clients to "com.sun.security.auth.module.JndiLoginModule", which can be done via the "producer.override.sasl.jaas.config", "consumer.override.sasl.jaas.config", or "admin.override.sasl.jaas.config" properties. This will allow the server to connect to the attacker's LDAP server and deserialize the LDAP response, which the attacker can use to execute java deserialization gadget chains on the Kafka connect server. Attackers can cause unrestricted deserialization of untrusted data (or) RCE vulnerability when there are gadgets in the classpath. Since Apache Kafka 3.0.0, users are allowed to specify these properties in connector configurations for Kafka Connect clusters running with out-of-the-box configurations. Before Apache Kafka 3.0.0, users may not specify these properties unless the Kafka Connect cluster has been reconfigured with a connector client override policy that permits them. 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. We advise Kafka Connect users to validate connector configurations and only allow trusted JNDI configurations. Also, examine connector dependencies for vulnerable versions and either upgrade their connectors, upgrading that specific dependency, or removing the connectors as options for remediation. Finally, in addition to leveraging the "org.apache.kafka.disallowed.login.modules" system property, Kafka Connect users can also implement their own connector client config override policy, which can be used to control which Kafka client properties can be overridden directly in a connector config and which cannot. This issue affects versions 2.3.0-rc1 through 3.3.2.
CWE-502 - Deserialization of Untrusted Data
Deserialization of untrusted data vulnerabilities enable an attacker to replace or manipulate a serialized object, replacing it with malicious data. When the object is deserialized at the victim's end the malicious data is able to compromise the victim’s system. The exploit can be devastating, its impact may range from privilege escalation, broken access control, or denial of service attacks to allowing unauthorized access to the application's internal code and logic which can compromise the entire system.