CVE-2023-25194

A possible security vulnerability has been identified in Apache Kafka
Connect API. 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 Connect 2.3.0. 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.
Attacker 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
Connect 3.4.0. We advise the 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.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=786460&gt;

Notes