CVE-2017-15697 in NiFi
Summary
by MITRE
A malicious X-ProxyContextPath or X-Forwarded-Context header containing external resources or embedded code could cause remote code execution. The fix to properly handle these headers 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-2017-15697 represents a critical remote code execution flaw within Apache NiFi, a robust data integration and processing platform designed for automating the movement of data between systems. This vulnerability specifically targets the handling of HTTP headers, particularly the X-ProxyContextPath and X-Forwarded-Context headers that are commonly used in reverse proxy configurations to maintain proper context paths for applications. The flaw stems from inadequate input validation and sanitization of these headers, allowing malicious actors to inject external resources or embedded code that could be executed within the NiFi application context. The vulnerability is classified under CWE-20 as "Improper Input Validation" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript" as the execution mechanism often involves JavaScript code injection. The affected Apache NiFi versions prior to 1.5.0 failed to properly sanitize these headers, creating a pathway for attackers to manipulate the application's behavior through crafted HTTP requests.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious HTTP requests containing specially formatted X-ProxyContextPath or X-Forwarded-Context headers that reference external resources or contain embedded code. These headers are typically used by reverse proxies to preserve the original context path when requests are forwarded to backend applications, but the improper handling allows attackers to inject malicious content that gets processed by NiFi's internal systems. The vulnerability is particularly dangerous because it can be exploited remotely without authentication, allowing attackers to execute arbitrary code on the NiFi server with the privileges of the NiFi process. This could lead to complete system compromise, data exfiltration, or disruption of data processing workflows that are critical to many organizations' operations.
The operational impact of CVE-2017-15697 extends beyond simple remote code execution, as it fundamentally undermines the security posture of NiFi installations that have not been upgraded to version 1.5.0 or later. Organizations running vulnerable versions face significant risk of unauthorized access to their data processing infrastructure, potentially leading to data breaches, system compromise, and disruption of critical data flows. The vulnerability affects any NiFi deployment that processes HTTP requests through reverse proxies or load balancers that forward these headers, making it particularly relevant for enterprise environments where NiFi is commonly deployed in production scenarios. The attack surface is broad since these headers are standard in many proxy configurations, and the vulnerability can be exploited through various attack vectors including web application firewalls, API endpoints, or direct network access to NiFi instances. Security teams must consider this vulnerability as a high-priority remediation item, especially in environments where NiFi is exposed to untrusted networks or where proper network segmentation is not in place.
Organizations should immediately upgrade to Apache NiFi version 1.5.0 or later to address this vulnerability, as the fix implemented in this release properly sanitizes and validates the X-ProxyContextPath and X-Forwarded-Context headers to prevent code injection attacks. The upgrade process should include thorough testing to ensure that existing proxy configurations continue to function correctly while benefiting from the enhanced security measures. Additionally, network administrators should implement proper monitoring and logging of HTTP headers to detect potential exploitation attempts, and consider implementing network-level controls such as firewall rules or web application firewalls to restrict access to NiFi instances. The mitigation strategy should also include regular security assessments of NiFi configurations and review of proxy settings to ensure that only legitimate headers are processed. Organizations should also consider implementing principle of least privilege access controls and network segmentation to limit the potential impact if exploitation occurs, as the vulnerability could be leveraged to gain elevated privileges within the NiFi environment.