CVE-2017-5636 in NiFi
Summary
by MITRE
In Apache NiFi before 0.7.2 and 1.x before 1.1.2 in a cluster environment, the proxy chain serialization/deserialization is vulnerable to an injection attack where a carefully crafted username could impersonate another user and gain their permissions on a replicated request to another node.
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Analysis
by VulDB Data Team • 01/19/2021
The vulnerability identified as CVE-2017-5636 represents a critical security flaw in Apache NiFi versions prior to 0.7.2 and 1.x versions before 1.1.2, specifically affecting cluster environments where proxy chain serialization and deserialization operations occur. This vulnerability stems from insufficient validation of user credentials during the replication process between nodes in a distributed NiFi setup, creating an exploitable injection vector that allows malicious actors to manipulate authentication data.
The technical flaw manifests in the improper handling of username data within the proxy chain mechanism that facilitates communication between nodes in a NiFi cluster. When a request is replicated to another node, the system deserializes user credentials without adequate sanitization or validation checks. This weakness enables an attacker to craft a specially formatted username field that bypasses normal authentication procedures and injects malicious data into the deserialization process. The vulnerability is particularly dangerous in cluster environments where multiple nodes share replicated requests and user permissions, as it allows attackers to impersonate legitimate users and assume their privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the integrity of NiFi's user authentication and authorization mechanisms. An attacker exploiting this vulnerability can gain unauthorized access to data and operations that should be restricted to specific user roles, potentially leading to complete system compromise. The attack requires minimal privileges to initiate, as the malicious username injection can occur during normal cluster communication, making detection difficult and the attack surface broad. This vulnerability directly relates to CWE-20, which addresses improper input validation, and aligns with ATT&CK technique T1078 for Valid Accounts and T1531 for Account Access Removal.
Mitigation strategies for CVE-2017-5636 require immediate implementation of the vendor-provided patches for Apache NiFi versions 0.7.2 and 1.1.2, which address the serialization/deserialization flaw in the proxy chain mechanism. Organizations should also implement network segmentation and access controls to limit cluster communication to trusted nodes only, reducing the attack surface available to potential exploiters. Additional defensive measures include monitoring for unusual authentication patterns, implementing robust logging of cluster replication activities, and conducting regular security audits of NiFi configurations. The fix specifically addresses the deserialization process by adding proper input validation and sanitization of username fields before they are processed in the proxy chain, preventing malicious injection attempts from succeeding.