CVE-2017-12632 in NiFi
Summary
by MITRE
A malicious host header in an incoming HTTP request could cause NiFi to load resources from an external server. The fix to sanitize host headers and compare to a controlled whitelist was applied on the Apache NiFi 1.5.0 release. Users running a prior 1.x release should upgrade to the appropriate release.
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Analysis
by VulDB Data Team • 12/27/2019
The vulnerability identified as CVE-2017-12632 represents a critical security flaw in Apache NiFi versions prior to 1.5.0, specifically targeting the application's handling of HTTP host headers. This issue stems from insufficient validation of incoming HTTP requests, allowing attackers to manipulate the host header field to redirect NiFi's resource loading behavior. The flaw enables a malicious actor to craft HTTP requests that cause NiFi to fetch resources from external servers, potentially leading to unauthorized data access or resource consumption. The vulnerability's impact is particularly concerning given NiFi's role as a data integration platform that processes sensitive information flows between systems, making it an attractive target for adversaries seeking to exploit weak authentication mechanisms or access control implementations. The root cause of this vulnerability aligns with CWE-20, which describes input validation issues where untrusted data is processed without adequate sanitization, and specifically relates to improper handling of HTTP headers in web applications.
The technical implementation of this vulnerability exploits the trust relationship between NiFi and its network components, particularly how the system interprets the host header field in HTTP requests. When NiFi processes incoming requests, it uses the host header to determine the target server for resource loading operations, but prior to version 1.5.0, it failed to validate or sanitize this input. This oversight creates a path for attackers to inject malicious host values that bypass normal access controls, potentially allowing them to access resources hosted on external domains or internal systems that should otherwise be protected from direct access. The vulnerability demonstrates poor input validation practices and lacks proper host header sanitization, which are fundamental security measures required for web applications to prevent header injection attacks. Security researchers identified that this flaw could enable attackers to perform unauthorized resource loading operations and potentially access sensitive data or system components that would normally be restricted to authenticated users within the NiFi environment.
The operational impact of CVE-2017-12632 extends beyond simple data exposure, as it could enable attackers to perform broader reconnaissance and potentially escalate privileges within the NiFi ecosystem. Attackers could leverage this vulnerability to access external resources that might contain malicious payloads or sensitive information, creating potential pathways for further exploitation within the network. The vulnerability's exploitation could result in data leakage, unauthorized access to internal systems, or even serve as a stepping stone for more sophisticated attacks targeting the broader network infrastructure. Organizations running affected NiFi versions face significant risk of unauthorized data access, particularly in environments where NiFi serves as a central hub for data flow management and where sensitive information is processed through the platform. The vulnerability's presence in production environments could compromise the integrity of data processing workflows and potentially violate regulatory compliance requirements for data protection and access control.
The mitigation strategy for CVE-2017-12632 centers on upgrading to Apache NiFi version 1.5.0 or later, which implements proper host header sanitization and validation mechanisms. This upgrade addresses the core issue by introducing a controlled whitelist approach for host header validation, ensuring that only pre-approved host values are accepted by the system. Organizations should also implement additional security measures such as network segmentation, firewall rules to restrict access to NiFi endpoints, and monitoring of HTTP traffic for suspicious host header values. The fix aligns with ATT&CK technique T1071.004, which covers protocol tunneling and header manipulation, demonstrating how proper input validation can prevent such exploitation methods. Security teams should conduct thorough testing of the upgrade process to ensure compatibility with existing NiFi configurations and workflows, while also implementing continuous monitoring to detect any attempts to exploit similar vulnerabilities in other components of their data integration infrastructure. Additionally, organizations should review their broader HTTP request handling processes to ensure similar vulnerabilities do not exist in other applications within their environment.