CVE-2018-10832 in ModbusPal
Summary
by MITRE
ModbusPal 1.6b is vulnerable to an XML External Entity (XXE) attack. Projects are saved as .xmpp files and automations can be exported as .xmpa files, both XML-based, which are vulnerable to XXE injection. Sending a crafted .xmpp or .xmpa file to a user, when opened/imported in ModbusPal, will return the contents of any local files to a remote attacker.
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Analysis
by VulDB Data Team • 11/13/2024
The vulnerability identified as CVE-2018-10832 represents a critical XML External Entity injection flaw in ModbusPal version 1.6b, a popular industrial automation tool used for simulating modbus devices and managing automation projects. This vulnerability stems from the application's improper handling of XML-based project files with extensions .xmpp and .xmpa, which are used for saving projects and exporting automations respectively. The flaw allows attackers to craft malicious XML files that can trigger unauthorized file access when these files are opened or imported into the application, creating a significant security risk for industrial control systems and automation environments.
The technical implementation of this vulnerability aligns with CWE-611, which specifically addresses XML External Entity processing without proper restrictions. ModbusPal's failure to sanitize XML input streams means that when the application parses .xmpp and .xmpa files, it processes external entity references that can be manipulated by attackers to access local system resources. The attack vector involves crafting specially designed XML content that includes external entity declarations pointing to local files or network resources, which are then processed by the application's XML parser. This processing occurs without adequate validation or restriction of external entity resolution, allowing the attacker to extract sensitive information from the victim's system.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to gain unauthorized access to system files, configuration data, and potentially sensitive operational information within industrial environments. In the context of industrial control systems, this vulnerability could compromise the integrity of automation projects and expose critical infrastructure data. The attack requires social engineering to deliver malicious files to targets, but once executed, it provides attackers with the ability to read arbitrary files from the victim's system, potentially including configuration files, project data, or other sensitive information that could be used for further attacks or system compromise. This vulnerability particularly affects environments where ModbusPal is used for industrial automation, SCADA systems, or any networked control environments where file import functionality is utilized.
Mitigation strategies for this vulnerability should focus on implementing proper XML parser configuration to disable external entity resolution and DTD processing. Security measures include updating to newer versions of ModbusPal that address this XXE vulnerability, implementing strict input validation for XML files, and configuring the application's XML parser to reject external entity references. Organizations should also consider implementing network segmentation and access controls to limit the impact of potential exploitation, while monitoring for suspicious file import activities. This vulnerability demonstrates the importance of secure XML processing in industrial automation tools and aligns with ATT&CK technique T1059.007 for XML external entity injection, emphasizing the need for robust input validation and secure coding practices in industrial control system software. The vulnerability highlights the critical nature of addressing XXE issues in industrial environments where automation tools are frequently used and where the potential for cascading security impacts is significant.