REDHAT-BUG-2333013: High severity Apache Kafka vulnerability
Incorrect Implementation of Authentication Algorithm in Apache Kafka's SCRAM implementation.
Issue Summary: Apache Kafka's implementation of the Salted Challenge Response Authentication Mechanism (SCRAM) did not fully adhere to the requirements of RFC 5802 [1]. Specifically, as per RFC 5802, the server must verify that the nonce sent by the client in the second message matches the nonce sent by the server in its first message. However, Kafka's SCRAM implementation did not perform this validation.
Impact: This vulnerability is exploitable only when an attacker has plaintext access to the SCRAM authentication exchange. However, the usage of SCRAM over plaintext is strongly discouraged as it is considered an insecure practice [2]. Apache Kafka recommends deploying SCRAM exclusively with TLS encryption to protect SCRAM exchanges from interception [3]. Deployments using SCRAM with TLS are not affected by this issue.
How to Detect If You Are Impacted: If your deployment uses SCRAM authentication over plaintext communication channels (without TLS encryption), you are likely impacted. To check if TLS is enabled, review your server.properties configuration file for listeners property. If you have SASLPLAINTEXT in the listeners, then you are likely impacted.
Fix Details: The issue has been addressed by introducing nonce verification in the final message of the SCRAM authentication exchange to ensure compliance with RFC 5802.
Affected Versions: Apache Kafka versions 0.10.2.0 through 3.9.0, excluding the fixed versions below.
Fixed Versions: 3.9.0 3.8.1 3.7.2
Users are advised to upgrade to 3.7.2 or later to mitigate this issue.
Recommendations for Mitigation: Users unable to upgrade to the fixed versions can mitigate the issue by: - Using TLS with SCRAM Authentication: Always deploy SCRAM over TLS to encrypt authentication exchanges and protect against interception. - Considering Alternative Authentication Mechanisms: Evaluate alternative authentication mechanisms, such as PLAIN, Kerberos or OAuth with TLS, which provide additional layers of security.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 3.7.2 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 3.8.1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 3.9.0 - Configuration
To check if you are impacted, review server.properties for the listeners property. If you have SASL_PLAINTEXT in the listeners, you are likely impacted; mitigate by avoiding SCRAM over plaintext by not configuring SASL_PLAINTEXT and instead using TLS-encrypted listeners for SCRAM.
Apache Kafka server.properties (listeners) listeners (SASL_PLAINTEXT presence) = Remove/avoid SASL_PLAINTEXT listener configurations - Configuration
Deploy SCRAM exclusively with TLS encryption to protect SCRAM exchanges from interception; deployments using SCRAM over TLS are not affected.
Apache Kafka SCRAM authentication Use of TLS with SCRAM = Use SCRAM exclusively with TLS encryption - Compensating control
Evaluate alternative authentication mechanisms (e.g., PLAIN, Kerberos, or OAuth) with TLS to add additional layers of security.
Event History
Frequently Asked Questions
What is the severity of REDHAT-BUG-2333013?
The severity of REDHAT-BUG-2333013 is determined based on its impact on the authentication mechanism in Apache Kafka, potentially affecting user security.
How do I fix REDHAT-BUG-2333013?
To fix REDHAT-BUG-2333013, it is recommended to update your Apache Kafka installation to the latest version that addresses this vulnerability.
What systems are affected by REDHAT-BUG-2333013?
REDHAT-BUG-2333013 affects all versions of Apache Kafka that utilize the SCRAM authentication mechanism.
What is the nature of the vulnerability in REDHAT-BUG-2333013?
The vulnerability in REDHAT-BUG-2333013 involves an incorrect implementation of the Salted Challenge Response Authentication Mechanism, which deviates from the specified standards.
Can REDHAT-BUG-2333013 lead to security breaches?
Yes, REDHAT-BUG-2333013 could potentially lead to security breaches due to improper authentication handling in affected systems.