CVE-2012-4710 in Wonderware Win-XML Exporter
Summary
by MITRE
Invensys Wonderware Win-XML Exporter 1522.148.0.0 allows remote attackers to read arbitrary files, send HTTP requests to intranet servers, or cause a denial of service (CPU and memory consumption) via an XML external entity declaration in conjunction with an entity reference.
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Analysis
by VulDB Data Team • 05/01/2017
The vulnerability identified as CVE-2012-4710 affects Invensys Wonderware Win-XML Exporter version 1522.148.0.0, presenting a critical security risk that stems from improper handling of XML external entity declarations. This flaw exists within the XML processing functionality of the software, specifically when processing XML documents that contain external entity references. The vulnerability is classified under CWE-611, which represents Improper Restriction of XML External Entity Reference, a well-documented weakness that has been exploited in numerous high-profile security incidents. The issue arises because the application fails to properly validate and restrict XML external entity declarations, allowing malicious actors to manipulate the XML parser behavior.
Attackers can exploit this vulnerability through several vectors including arbitrary file reading, internal network HTTP requests, and denial of service conditions. When an XML document containing malicious external entity declarations is processed, the system may attempt to resolve these entities, potentially leading to unauthorized access to local files on the server. This capability enables attackers to read sensitive data from the local filesystem, including configuration files, user credentials, or proprietary information. The vulnerability also permits attackers to initiate HTTP requests to internal network servers, effectively bypassing network segmentation and potentially escalating privileges or accessing restricted internal resources. The XML external entity processing can be manipulated to consume excessive CPU and memory resources, resulting in denial of service conditions that can bring the targeted system to its knees.
The operational impact of this vulnerability extends beyond simple data exposure, as it creates a comprehensive attack surface that can be leveraged for various malicious activities. The ability to perform arbitrary file reads represents a severe information disclosure risk, potentially exposing sensitive corporate data or system configuration details. Network-based attacks through internal HTTP requests can be particularly dangerous in industrial control environments where network segmentation is critical for operational technology security. The denial of service component can disrupt critical business operations, especially in environments where the Win-XML Exporter is integral to industrial processes. This vulnerability aligns with ATT&CK technique T1566, which covers the exploitation of XML external entity vulnerabilities for information gathering and system disruption. The attack can be executed remotely without requiring authentication, making it particularly dangerous for systems accessible from the internet or exposed to untrusted networks.
Organizations should implement multiple layers of defense to mitigate this vulnerability effectively. Immediate remediation involves applying patches provided by Invensys or upgrading to versions that address the XML external entity processing flaw. Network segmentation should be enforced to limit access to the affected system, ensuring that only trusted sources can communicate with the Win-XML Exporter service. Input validation and sanitization should be implemented at all levels of the application stack to prevent malicious XML content from reaching the vulnerable parser. Security monitoring should be enhanced to detect unusual patterns of file access or network requests originating from the affected system. The vulnerability demonstrates the importance of proper XML parsing security practices, as outlined in industry standards and best practices for secure coding. Organizations should also consider implementing web application firewalls or XML gateways that can filter malicious external entity declarations before they reach the vulnerable application components. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other applications and systems within the organization's infrastructure.