CVE-2018-17196 in Primavera Unifier
Summary
by MITRE
In Apache Kafka versions between 0.11.0.0 and 2.1.0, it is possible to manually craft a Produce request which bypasses transaction/idempotent ACL validation. Only authenticated clients with Write permission on the respective topics are able to exploit this vulnerability. Users should upgrade to 2.1.1 or later where this vulnerability has been fixed.
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Analysis
by VulDB Data Team • 11/23/2020
The vulnerability described in CVE-2018-17196 represents a significant authorization bypass flaw in Apache Kafka that affects versions from 0.11.0.0 through 2.1.0. This issue specifically targets the transactional and idempotent producer functionality within the messaging system, creating a scenario where authenticated users can circumvent access control mechanisms that should normally restrict write operations to specific topics. The flaw exists in the validation logic that governs how produce requests are processed, particularly when dealing with transactional and idempotent operations that require strict access controls to maintain data integrity and security boundaries.
The technical implementation of this vulnerability stems from an insufficient validation mechanism that fails to properly enforce Access Control List (ACL) checks during the processing of manually crafted Produce requests. When a client sends a produce request that includes transactional or idempotent parameters, the system should verify that the authenticated user possesses the appropriate Write permissions on the target topics before allowing the operation to proceed. However, the vulnerability allows malicious actors to bypass these checks by carefully constructing specific request parameters that exploit gaps in the validation logic. This particular flaw falls under the CWE-284 category of Improper Access Control, where the system fails to properly enforce access restrictions that should prevent unauthorized operations.
The operational impact of this vulnerability is substantial for organizations relying on Kafka for mission-critical messaging systems, as it enables authenticated users with Write permissions on topics to potentially perform unauthorized operations that could compromise data integrity and system security. While the vulnerability requires authentication and existing Write permissions on topics, it creates a scenario where attackers can manipulate the system behavior to bypass additional transactional safety mechanisms that are designed to prevent data corruption and maintain consistency. This could lead to data loss, unauthorized message publication, or potential disruption of service continuity in environments where strict access controls are essential for maintaining data governance policies.
Organizations affected by this vulnerability should immediately implement the recommended mitigation strategy of upgrading to Apache Kafka version 2.1.1 or later, where the fix has been properly implemented. The upgrade process should include thorough testing to ensure that existing applications continue to function correctly with the updated security controls. Additionally, system administrators should review existing ACL configurations to ensure that proper access controls are in place and that only authorized users have Write permissions on sensitive topics. The vulnerability demonstrates the importance of maintaining current security patches and the critical nature of proper access control validation in distributed messaging systems. This issue aligns with ATT&CK technique T1078.004 for Valid Accounts and T1566.001 for Phishing, as it leverages authenticated access to escalate privileges within the messaging infrastructure. Organizations should also consider implementing additional monitoring and logging of produce requests to detect anomalous patterns that might indicate exploitation attempts, as the vulnerability could potentially be used as part of a broader attack chain targeting messaging infrastructure components.