CVE-2013-0686 in Wonderware Information Server
Summary
by MITRE
Invensys Wonderware Information Server (WIS) 4.0 SP1SP1, 4.5- Portal, and 5.0- Portal 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 • 05/02/2017
The vulnerability identified as CVE-2013-0686 represents a critical XML External Entity (XXE) flaw affecting Invensys Wonderware Information Server versions 4.0 SP1SP1, 4.5-Portal, and 5.0-Portal. This security weakness stems from the application's improper handling of XML documents that contain external entity declarations, creating a pathway for malicious actors to exploit the system through carefully crafted XML input. The vulnerability is classified under CWE-611, which specifically addresses Improper Restriction of XML External Entity Reference, making it a direct descendant of well-known XML parsing security issues that have plagued numerous enterprise applications over the years. The XXE vulnerability exists because the Information Server fails to adequately validate or sanitize XML input, allowing attackers to reference external entities that can be exploited for various malicious purposes.
The technical exploitation of this vulnerability enables remote attackers to perform three distinct types of malicious activities through a single attack vector. First, adversaries can read arbitrary files from the server's file system, potentially accessing sensitive configuration files, credentials, or proprietary data that should remain protected. Second, the vulnerability permits attackers to send HTTP requests to intranet servers, effectively using the Information Server as a proxy to bypass network segmentation and access internal systems that would normally be restricted. Third, the flaw can be leveraged to cause denial of service conditions by consuming excessive CPU and memory resources, potentially leading to system crashes or significant performance degradation that impacts business operations. This multi-faceted attack capability makes the vulnerability particularly dangerous as it combines information disclosure, lateral movement, and availability disruption in a single exploit.
From an operational perspective, the impact of CVE-2013-0686 extends beyond immediate security breaches to potentially compromise entire industrial control systems that rely on Wonderware Information Server for data management and communication. The vulnerability's remote exploitability means that attackers do not require physical access to the network or system, making it an attractive target for cybercriminals seeking to gain unauthorized access to industrial environments. The ability to read arbitrary files could expose sensitive industrial data, system configurations, or authentication credentials that could be used for further attacks within the industrial ecosystem. The HTTP request forwarding capability poses significant risks to internal network security, as it allows attackers to probe and potentially compromise systems that are normally isolated from external network traffic. Additionally, the denial of service component can severely impact operational continuity, particularly in environments where uninterrupted access to information systems is critical for industrial processes and safety monitoring.
Organizations affected by this vulnerability should implement immediate mitigations to protect their Wonderware Information Server deployments. The primary defense mechanism involves disabling external entity processing in XML parsers and ensuring that all XML input is properly validated and sanitized before processing. Security measures should include implementing strict XML schema validation, configuring firewalls to restrict access to internal systems, and monitoring network traffic for suspicious HTTP request patterns. The ATT&CK framework categorizes this vulnerability under T1068, which covers "Exploitation for Privilege Escalation," as well as T1190, which addresses "Exploit Public-Facing Application" techniques. Organizations should also consider implementing network segmentation to limit the potential impact of successful exploitation, deploy intrusion detection systems to monitor for XXE attack patterns, and ensure that all systems are updated with the latest security patches provided by Invensys. Regular security assessments and penetration testing should be conducted to verify that the implemented mitigations are effective and to identify any additional vulnerabilities that may exist within the industrial control system environment.