CVE-2018-7837 in Monitor
Summary
by MITRE
An Improper Restriction of XML External Entity Reference ('XXE') vulnerability exists on numerous methods of the IIoT Monitor 3.1.38 software that could allow the software to resolve documents outside of the intended sphere of control, causing the software to embed incorrect documents into its output and expose restricted information.
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Analysis
by VulDB Data Team • 04/24/2020
The CVE-2018-7837 vulnerability represents a critical xml external entity reference flaw in IIoT Monitor 3.1.38 software, classified under CWE-611 as improper restriction of xml external entity references. This vulnerability stems from the software's inadequate handling of xml input processing, where it fails to properly validate or sanitize xml documents before parsing. The flaw allows attackers to manipulate xml parsers by introducing external entity references that can cause the software to access and process files from unintended locations within the system's file structure. The vulnerability affects multiple methods within the IIoT Monitor software, indicating a systemic issue rather than isolated function flaws.
The technical exploitation of this vulnerability enables attackers to perform unauthorized information disclosure through xml external entity expansion. When the software processes xml data containing malicious external entity references, it can resolve these references and incorporate the referenced content into its output streams. This creates a pathway for attackers to access restricted files, system information, or other sensitive data that should remain protected within the software's operational boundaries. The vulnerability's impact extends beyond simple data exposure as it can potentially allow for further exploitation through chained attacks that leverage the information gained from the initial XXE payload.
The operational implications of CVE-2018-7837 are particularly severe in industrial internet of things environments where IIoT Monitor software typically operates. The vulnerability can compromise the integrity of industrial control systems by exposing configuration files, authentication credentials, or operational data that could be used for lateral movement within the network. Attackers could leverage this vulnerability to gain insights into system architecture, network topology, and operational procedures that would normally be restricted to authorized personnel only. The presence of this flaw in a monitoring system specifically designed for industrial environments creates a significant risk to operational technology security and potentially physical safety systems.
Security mitigations for CVE-2018-7837 should focus on implementing comprehensive xml parsing controls that prevent external entity resolution and restrict access to local resources. Organizations should disable external entity processing in all xml parsers used by the IIoT Monitor software and implement strict input validation for all xml data. The solution involves configuring xml parsers to reject any xml content that contains external entity declarations or references to local files. Additionally, network segmentation and access controls should be implemented to limit the potential impact of successful exploitation. This vulnerability aligns with ATT&CK technique T1059.007 for xml external entity processing and represents a common attack vector in industrial control system environments where xml processing is prevalent. System administrators should also consider implementing xml schema validation and content filtering to prevent malicious xml content from being processed by the software.