CVE-2017-15703 in NiFi
Summary
by MITRE
Any authenticated user (valid client certificate but without ACL permissions) could upload a template which contained malicious code and caused a denial of service via Java deserialization attack. The fix to properly handle Java deserialization was applied on the Apache NiFi 1.4.0 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
This vulnerability resides within Apache NiFi, a powerful data processing and routing platform that handles sensitive information flows across organizations. The flaw specifically targets the template upload functionality within the system, creating a critical security gap that allows authenticated users with valid client certificates to exploit the platform through a Java deserialization attack. The vulnerability stems from insufficient input validation and improper handling of serialized Java objects during template processing, enabling malicious actors to craft specially designed template files that contain serialized malicious code.
The technical implementation of this vulnerability exploits the Java deserialization mechanism within NiFi's template processing pipeline. When an authenticated user uploads a template file, the system attempts to deserialize the content to process the template structure. However, the system fails to properly validate or sanitize the serialized data, allowing attackers to inject malicious serialized objects that can execute arbitrary code on the target system. This particular vulnerability is classified under CWE-502, which specifically addresses deserialization of untrusted data, making it a prime target for remote code execution and denial of service attacks. The attack vector leverages the fact that the system does not properly validate the contents of uploaded templates, creating a pathway for malicious code execution through the Java deserialization process.
The operational impact of this vulnerability extends beyond simple denial of service, as it fundamentally compromises the security posture of Apache NiFi installations. An attacker with valid client certificate credentials but without explicit ACL permissions can leverage this flaw to cause system-wide disruption, potentially leading to complete service outages. The vulnerability affects the availability and integrity of the data processing pipeline, as malicious templates can cause the NiFi instance to crash or become unresponsive. This represents a significant risk in enterprise environments where NiFi serves as a critical component for data flow management, as unauthorized users could disrupt business operations and potentially gain further access to downstream systems. The attack requires only authentication credentials, making it particularly dangerous as it can be exploited by insiders or compromised accounts.
Mitigation strategies for this vulnerability require immediate action through proper system updates and configuration hardening. Organizations must upgrade to Apache NiFi version 1.4.0 or later, which includes the necessary fixes to properly handle Java deserialization attacks. Beyond the mandatory upgrade, system administrators should implement additional security controls including strict template validation, monitoring of template upload activities, and network segmentation to limit potential attack surfaces. The fix addresses the core deserialization issue by implementing proper input sanitization and object validation mechanisms, aligning with ATT&CK technique T1203 for legitimate credentials and T1059 for command and scripting interpreter usage. Security teams should also consider implementing web application firewalls and intrusion detection systems to monitor for suspicious template upload patterns and potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to ensure the continued integrity of NiFi installations against similar attack vectors.