CVE-2018-6911 in WebAccess
Summary
by MITRE
The VBWinExec function in Node\AspVBObj.dll in Advantech WebAccess 8.3.0 allows remote attackers to execute arbitrary OS commands via a single argument (aka the command parameter).
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Analysis
by VulDB Data Team • 10/20/2025
The vulnerability identified as CVE-2018-6911 resides within the Advantech WebAccess 8.3.0 software platform, specifically within the VBWinExec function located in the Node\AspVBObj.dll component. This critical security flaw represents a command injection vulnerability that enables remote attackers to execute arbitrary operating system commands on the affected system. The vulnerability manifests through a single argument parameter, commonly referred to as the command parameter, which lacks proper input validation and sanitization mechanisms. The flaw exists in the context of web-based applications that utilize Advantech's WebAccess platform for industrial automation and monitoring purposes, making it particularly concerning for operational technology environments where system integrity and security are paramount.
This vulnerability directly maps to CWE-78, which describes improper neutralization of special elements used in OS commands, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter. The technical implementation flaw occurs when the VBWinExec function processes user-supplied input without adequate sanitization, allowing attackers to inject malicious commands that are subsequently executed by the underlying operating system. The single argument parameter serves as the attack vector where an attacker can append additional commands using operating system-specific syntax such as semicolons, ampersands, or other command chaining operators. This vulnerability essentially provides an attacker with a direct pathway to execute arbitrary code on the target system, potentially leading to complete system compromise and unauthorized access to industrial control systems.
The operational impact of CVE-2018-6911 extends beyond traditional network security concerns into critical infrastructure domains where Advantech WebAccess is commonly deployed. Organizations utilizing this software in manufacturing environments, process control systems, or other industrial applications face severe risks including unauthorized system access, data exfiltration, and potential disruption of critical operations. The remote exploitability of this vulnerability means that attackers can leverage it from outside the network perimeter without requiring physical access or prior authentication, making it particularly dangerous for industrial environments where network segmentation may be limited. The implications are especially grave in environments where the software controls critical machinery or processes, as successful exploitation could lead to production disruptions, safety hazards, or even physical damage to equipment.
Mitigation strategies for CVE-2018-6911 should prioritize immediate patching of the affected Advantech WebAccess 8.3.0 software to the latest available version that addresses this vulnerability. Organizations should implement network segmentation and access controls to limit exposure of the affected systems to untrusted networks, while also deploying intrusion detection systems to monitor for suspicious command execution patterns. Input validation and sanitization measures should be implemented at the application level to prevent malicious command injection attempts, and administrators should regularly audit system logs for evidence of unauthorized command execution. Additionally, implementing principle of least privilege access controls and disabling unnecessary services can reduce the attack surface. Organizations should also consider deploying web application firewalls to filter and monitor HTTP requests that may contain malicious command injection payloads, while maintaining comprehensive backup and recovery procedures to ensure business continuity in case of successful exploitation. The vulnerability highlights the importance of secure coding practices and regular security assessments in industrial control systems where software security is often overlooked in favor of operational functionality.