CVE-2017-16736 in WebAccess
Summary
by MITRE
An Unrestricted Upload Of File With Dangerous Type issue was discovered in Advantech WebAccess versions prior to 8.3. WebAccess allows a remote attacker to upload arbitrary files.
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Analysis
by VulDB Data Team • 12/22/2019
The vulnerability identified as CVE-2017-16736 represents a critical security flaw in Advantech WebAccess software versions prior to 8.3, classified under the Common Weakness Enumeration category CWE-434 which specifically addresses unrestricted file uploads. This vulnerability creates a pathway for remote attackers to exploit the system by uploading arbitrary files, fundamentally undermining the security posture of industrial automation and monitoring platforms. The flaw exists within the file upload functionality of the WebAccess platform, which is widely deployed in industrial environments for supervisory control and data acquisition systems.
The technical implementation of this vulnerability stems from insufficient validation and sanitization of file upload operations within the WebAccess application. Attackers can leverage this weakness to bypass security controls and upload malicious files such as web shells, executables, or script files that can be executed within the target system. The unrestricted nature of the upload mechanism means that the application does not properly validate file types, extensions, or content, allowing attackers to upload files with dangerous extensions that can execute code on the server. This type of vulnerability is particularly concerning in industrial control systems where WebAccess is commonly deployed, as it can lead to complete system compromise and potential operational technology disruptions.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads, creating a significant attack surface that can be exploited for various malicious activities including privilege escalation, persistent backdoor establishment, and lateral movement within network environments. In industrial settings, this vulnerability could enable attackers to gain unauthorized access to critical infrastructure monitoring systems, potentially leading to operational disruptions, data breaches, or even physical safety hazards. The remote exploitation capability means that attackers do not require physical access to the system, making the vulnerability particularly dangerous in environments where network security controls may be insufficient.
Organizations should implement immediate mitigations including applying the vendor-provided security patches for WebAccess version 8.3 or later, which address the file upload validation issues. Network segmentation and firewall rules should be implemented to restrict access to WebAccess systems, while implementing proper file type validation and content scanning mechanisms. The vulnerability aligns with ATT&CK technique T1195 which covers content injection attacks, and T1059 which covers command and scripting interpreter usage, as attackers can leverage this vulnerability to execute malicious code. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in industrial control systems, as the interconnected nature of these environments makes them particularly susceptible to cascading security incidents.