Package Instance

Apache Kafka Clients: Privilege escalation to filesystem read-access via automatic ConfigProvider
Files or Directories Accessible to External Parties, Improper Privilege Management vulnerability in Apache Kafka Clients.

Apache Kafka Clients accept configuration data for customizing behavior, and includes ConfigProvider plugins in order to manipulate these configurations. Apache Kafka also provides FileConfigProvider, DirectoryConfigProvider, and EnvVarConfigProvider implementations which include the ability to read from disk or environment variables.
In applications where Apache Kafka Clients configurations can be specified by an untrusted party, attackers may use these ConfigProviders to read arbitrary contents of the disk and environment variables.

In particular, this flaw may be used in Apache Kafka Connect to escalate from REST API access to filesystem/environment access, which may be undesirable in certain environments, including SaaS products.
This issue affects Apache Kafka Clients: from from 2.3.0 through 3.5.2, 3.6.0 through 3.6.2, and 3.7.0.


Users with affected applications are recommended to upgrade kafka-clients to version >=3.8.0, and set the JVM system property "org.apache.kafka.automatic.config.providers=none".
Users of Kafka Connect with one of the listed ConfigProvider implementations specified in their worker config are also recommended to add appropriate "allowlist.pattern" and "allowed.paths" to restrict their operation to appropriate bounds.


For users of Kafka Clients or Kafka Connect in environments that trust users with disk and environment variable access, it is not recommended to set the system property.
For users of the Kafka Broker, Kafka MirrorMaker 2.0, Kafka Streams, and Kafka command-line tools, it is not recommended to set the system property.

Apache Kafka Client Arbitrary File Read and Server Side Request Forgery Vulnerability
A possible arbitrary file read and SSRF vulnerability has been identified in Apache Kafka Client. Apache Kafka Clients accept configuration data for setting the SASL/OAUTHBEARER connection with the brokers, including "sasl.oauthbearer.token.endpoint.url" and "sasl.oauthbearer.jwks.endpoint.url". Apache Kafka allows clients to read an arbitrary file and return the content in the error log, or sending requests to an unintended location. In applications where Apache Kafka Clients configurations can be specified by an untrusted party, attackers may use the "sasl.oauthbearer.token.endpoint.url" and "sasl.oauthbearer.jwks.endpoint.url" configuratin to read arbitrary contents of the disk and environment variables or make requests to an unintended location. In particular, this flaw may be used in Apache Kafka Connect to escalate from REST API access to filesystem/environment/URL access, which may be undesirable in certain environments, including SaaS products. 

Since Apache Kafka 3.9.1/4.0.0, we have added a system property ("-Dorg.apache.kafka.sasl.oauthbearer.allowed.urls") to set the allowed urls in SASL JAAS configuration. In 3.9.1, it accepts all urls by default for backward compatibility. However in 4.0.0 and newer, the default value is empty list and users have to set the allowed urls explicitly.