CVE-2012-4709 in Wonderware InTouch
Summary
by MITRE
Invensys Wonderware InTouch HMI 2012 R2 and earlier 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 document containing an external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.
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Analysis
by VulDB Data Team • 05/13/2017
The vulnerability identified as CVE-2012-4709 represents a critical XML External Entity (XXE) flaw within Invensys Wonderware InTouch HMI 2012 R2 and earlier versions. This issue resides in the software's XML parser implementation which fails to properly validate and sanitize external entity declarations. The vulnerability specifically affects industrial automation systems that utilize Wonderware's Human Machine Interface platform, creating a significant security risk for critical infrastructure environments where such systems are deployed.
The technical exploitation of this XXE vulnerability occurs when an attacker crafts a malicious XML document containing external entity declarations that reference local files or network resources. When the vulnerable InTouch HMI system processes this XML content, it automatically resolves the external entity references, enabling unauthorized access to arbitrary files on the system's filesystem. The attack vector allows for both information disclosure and potential remote code execution depending on the system configuration and file permissions. This flaw maps directly to CWE-611, which specifically addresses XML external entity processing vulnerabilities, and aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments.
The operational impact of this vulnerability extends beyond simple file reading capabilities to include the ability to send HTTP requests to intranet servers, effectively enabling attackers to perform internal network reconnaissance and potentially exploit other systems within the organization's network. Furthermore, the vulnerability can be leveraged to cause denial of service conditions by consuming excessive CPU and memory resources through malicious entity references. This multi-faceted attack capability makes the vulnerability particularly dangerous in industrial control systems where availability and integrity of operations are paramount. The resource exhaustion aspect of the vulnerability can lead to system crashes or unresponsive states that could compromise critical manufacturing or operational processes.
Organizations utilizing Wonderware InTouch HMI systems should immediately implement mitigations including disabling external entity resolution in XML parsers, implementing strict input validation for all XML content, and deploying network segmentation to limit potential attack surfaces. The recommended approach involves configuring the XML parser to reject external entity declarations and references, which directly addresses the root cause of the vulnerability. Additionally, network-based protections such as firewalls and intrusion detection systems should be configured to monitor for suspicious XML traffic patterns. System administrators should also consider implementing application-level restrictions that prevent the processing of untrusted XML content, particularly in environments where industrial control systems interact with external networks. This vulnerability highlights the critical importance of secure coding practices in industrial software and demonstrates how legacy systems often lack proper input validation mechanisms that could prevent such exploitation scenarios.