CVE-2018-8841 in WebAccess
Summary
by MITRE
In Advantech WebAccess versions V8.2_20170817 and prior, WebAccess versions V8.3.0 and prior, WebAccess Dashboard versions V.2.0.15 and prior, WebAccess Scada Node versions prior to 8.3.1, and WebAccess/NMS 2.0.3 and prior, an improper privilege management vulnerability may allow an authenticated user to modify files when read access should only be given to the user.
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Analysis
by VulDB Data Team • 02/05/2020
The vulnerability identified as CVE-2018-8841 represents a critical improper privilege management flaw within Advantech WebAccess industrial automation software platforms. This security weakness affects multiple product variants including WebAccess V8.2 through V8.3, WebAccess Dashboard, Scada Node, and WebAccess/NMS versions up to 2.0.3. The vulnerability stems from inadequate access control mechanisms that fail to properly enforce privilege boundaries, allowing authenticated users to escalate their permissions beyond what is intended for their role. This misconfiguration creates a dangerous situation where users with read-only access can potentially modify critical system files and configuration data, undermining the fundamental security model of the industrial control system.
The technical implementation of this vulnerability manifests through flawed authorization checks within the WebAccess platform's file management subsystem. When users authenticate to the system, the privilege management logic fails to properly validate whether the requesting user has adequate permissions to perform write operations on specific files or directories. This weakness can be exploited by an authenticated attacker who, despite possessing only read access rights, can manipulate the system's permission controls to gain write privileges. The flaw typically occurs during file operations where the system does not adequately verify the user's privilege level against the requested action, creating a path for privilege escalation through carefully crafted file modification requests. This issue falls under the CWE-276 category of incorrect access control, specifically addressing improper privilege management within software applications.
The operational impact of CVE-2018-8841 extends far beyond simple unauthorized file modifications, as it fundamentally compromises the integrity and security posture of industrial control systems. An attacker exploiting this vulnerability can modify configuration files, alter operational parameters, or even inject malicious code into the control system, potentially leading to operational disruptions, safety hazards, or complete system compromise. The implications are particularly severe in industrial environments where WebAccess is commonly deployed for critical infrastructure monitoring and control, as unauthorized modifications could affect production processes, safety systems, or regulatory compliance measures. This vulnerability undermines the principle of least privilege that is fundamental to industrial cybersecurity frameworks and can result in cascading security failures throughout the connected industrial network.
Organizations affected by this vulnerability should implement immediate mitigations including updating to the latest available versions of Advantech WebAccess software where patches are provided. The vendor has released updates addressing this specific privilege management issue, and administrators should prioritize deployment of these security patches across all affected systems. Network segmentation and access control measures should be enhanced to limit user access to only necessary system components, while monitoring should be implemented to detect unauthorized file modification attempts. Additionally, regular security assessments and privilege reviews should be conducted to ensure that user access rights align with their operational requirements. This vulnerability demonstrates the importance of proper access control implementation in industrial environments and aligns with ATT&CK techniques related to privilege escalation and persistence within industrial control systems. Organizations should also consider implementing additional security controls such as file integrity monitoring, privileged access management solutions, and comprehensive security awareness training for system administrators to prevent exploitation of similar vulnerabilities in the future.