CVE-2017-5635 in NiFi
Summary
by MITRE
In Apache NiFi before 0.7.2 and 1.x before 1.1.2 in a cluster environment, if an anonymous user request is replicated to another node, the originating node identity is used rather than the "anonymous" user.
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Analysis
by VulDB Data Team • 11/27/2019
The vulnerability described in CVE-2017-5635 affects Apache NiFi versions prior to 0.7.2 and 1.x versions prior to 1.1.2 within cluster environments. This issue represents a significant authentication and authorization flaw that undermines the security model of distributed NiFi deployments. The vulnerability specifically manifests when anonymous user requests are processed across multiple nodes in a cluster configuration, creating a scenario where security contexts become misaligned between nodes.
The technical flaw stems from improper handling of user identity propagation within NiFi's cluster architecture. When an anonymous user makes a request that gets replicated to another node in the cluster, the system fails to properly establish the anonymous user context on the receiving node. Instead, the originating node's identity information is carried forward, effectively allowing unauthorized access patterns to persist across cluster nodes. This behavior creates a situation where legitimate security controls designed to isolate anonymous users from authenticated sessions are bypassed through node-to-node replication mechanisms.
From an operational impact perspective, this vulnerability enables attackers to potentially exploit the inconsistency in user identity handling across cluster nodes. An attacker who gains access to one node in a cluster could potentially leverage this flaw to maintain access or escalate privileges when requests are replicated to other nodes. The issue is particularly concerning in clustered environments where multiple nodes work together to process requests, as it creates a vector for privilege escalation and unauthorized access that could compromise the entire cluster's security posture.
The vulnerability aligns with CWE-285, which addresses improper authorization issues in distributed systems, and relates to ATT&CK technique T1078.004 for Valid Accounts - Cloud Accounts, as it enables unauthorized access through improper identity handling. Organizations using Apache NiFi in cluster configurations should prioritize immediate patching to address this vulnerability, ensuring that all nodes in the cluster properly maintain the anonymous user context when processing replicated requests.
Mitigation strategies should include updating to Apache NiFi versions 0.7.2 or 1.1.2 and higher, implementing proper access controls, and monitoring cluster node communications for anomalous behavior. Additionally, organizations should review their NiFi cluster configurations to ensure that proper user context isolation is maintained across all nodes, particularly in environments where anonymous access is permitted. Regular security assessments of cluster configurations and user identity management processes are essential to prevent exploitation of similar vulnerabilities in the future.