CVE-2017-5643 in Camel
Summary
by MITRE
Apache Camel's Validation Component is vulnerable against SSRF via remote DTDs and XXE.
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Analysis
by VulDB Data Team • 09/09/2020
The vulnerability identified as CVE-2017-5643 affects Apache Camel's Validation Component, which is a critical security flaw that enables server-side request forgery attacks through remote document type definitions and XML external entity exploitation. This vulnerability resides within the component's XML parsing functionality that processes validation requests, creating a pathway for attackers to manipulate the system's behavior by injecting malicious XML content. The issue manifests when the Validation Component accepts XML input that includes external entity declarations or references to remote DTD files, allowing unauthorized access to internal resources that should remain protected from external interference.
The technical flaw stems from insufficient input validation and sanitization within Apache Camel's XML processing pipeline, specifically in how it handles external entity resolution during XML validation operations. When a malicious user submits XML content containing references to remote DTD files or external entities, the system attempts to resolve these references without proper authorization checks, leading to potential information disclosure and unauthorized resource access. This vulnerability operates at the application layer and can be exploited through various attack vectors that leverage XML parsing mechanisms to bypass normal security controls. The flaw is particularly dangerous because it allows attackers to perform requests to internal systems that would normally be inaccessible from external networks, effectively creating a tunnel through the network's security boundaries.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to perform reconnaissance activities against internal network resources, potentially leading to further exploitation opportunities within the organization's infrastructure. Attackers can leverage this vulnerability to access internal services, databases, or file systems that are typically protected by firewalls or other network security controls. The vulnerability affects systems running Apache Camel versions prior to 2.19.0, making it a significant concern for organizations that have not yet upgraded their components. The attack surface is particularly wide because XML validation is a common operation in many applications, and the vulnerability can be triggered through various input points where XML content is processed.
Organizations should implement immediate mitigations including upgrading to Apache Camel version 2.19.0 or later, which contains patches addressing the XML external entity processing issues. Network segmentation and firewall rules should be configured to restrict access to internal resources from the affected systems, while also implementing proper input validation and sanitization measures. The vulnerability aligns with CWE-611 (Improper Restriction of XML External Entity Reference) and can be mapped to ATT&CK technique T1071.004 (Application Layer Protocol: DNS) when used for reconnaissance activities. Additionally, organizations should consider implementing XML parser configurations that disable external entity resolution entirely, and establish monitoring protocols to detect suspicious XML processing activities that may indicate exploitation attempts. Security teams should also conduct thorough assessments of their Apache Camel implementations to identify all potential entry points where this vulnerability could be exploited and ensure proper security controls are in place to prevent unauthorized access to internal systems.