Kafka ACL Ignored When Migrating from ZK to KRaft, Allowing Unauthorized Access
CVE-2024-27309 Published on April 12, 2024
Apache Kafka: Potential incorrect access control during migration from ZK mode to KRaft mode
While an Apache Kafka cluster is being migrated from ZooKeeper mode to KRaft mode, in some cases ACLs will not be correctly enforced.
Two preconditions are needed to trigger the bug:
1. The administrator decides to remove an ACL
2. The resource associated with the removed ACL continues to have two or more other ACLs associated with it after the removal.
When those two preconditions are met, Kafka will treat the resource as if it had only one ACL associated with it after the removal, rather than the two or more that would be correct.
The incorrect condition is cleared by removing all brokers in ZK mode, or by adding a new ACL to the affected resource. Once the migration is completed, there is no metadata loss (the ACLs all remain).
The full impact depends on the ACLs in use. If only ALLOW ACLs were configured during the migration, the impact would be limited to availability impact. if DENY ACLs were configured, the impact could include confidentiality and integrity impact depending on the ACLs configured, as the DENY ACLs might be ignored due to this vulnerability during the migration period.
Vulnerability Analysis
CVE-2024-27309 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.
Weakness Type
What is an AuthZ Vulnerability?
The software performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.
CVE-2024-27309 has been classified to as an AuthZ vulnerability or weakness.
Products Associated with CVE-2024-27309
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Affected Versions
Apache Software Foundation Apache Kafka:- Version 3.5.0, <= 3.5.2 is affected.
- Version 3.6.0, <= 3.6.1 is affected.
- Version 3.5.0, <= 3.5.2 is affected.
- Version 3.6.0, <= 3.6.1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.