CVE-2016-4525 in WebAccess
Summary
by MITRE
Unspecified ActiveX controls in Advantech WebAccess before 8.1_20160519 allow remote authenticated users to obtain sensitive information or modify data via unknown vectors, related to the INTERFACESAFE_FOR_UNTRUSTED_CALLER (aka safe for scripting) flag.
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Analysis
by VulDB Data Team • 02/09/2019
The vulnerability identified as CVE-2016-4525 affects Advantech WebAccess software versions prior to 8.1_20160519 and involves unspecified ActiveX controls that present security risks to remote authenticated users. This flaw specifically relates to the INTERFACESAFE_FOR_UNTRUSTED_CALLER flag, which is a critical component in COM component security modeling. The vulnerability allows attackers who have already gained authentication credentials to potentially access sensitive information or modify data within the system, representing a significant escalation of privileges that could be exploited in targeted attacks against industrial control systems.
The technical root cause of this vulnerability stems from improper handling of the safe for scripting flag within ActiveX controls that are part of the Advantech WebAccess platform. When a COM object is marked as INTERFACESAFE_FOR_UNTRUSTED_CALLER, it indicates that the object can be safely called from untrusted code, but this designation can be misused when combined with other security flaws. The vulnerability manifests through unknown vectors that exploit the trust model established by this flag, allowing authenticated attackers to bypass normal access controls that should prevent unauthorized data access or modification. This represents a classic case of privilege escalation through flawed security boundaries in component-based applications.
The operational impact of CVE-2016-4525 extends beyond simple information disclosure to include potential data integrity compromise within industrial automation environments. Organizations using Advantech WebAccess systems face risks of unauthorized data modification that could affect critical processes, leading to operational disruptions or safety hazards in industrial settings. The vulnerability is particularly concerning in environments where these systems control manufacturing processes, power generation, or other critical infrastructure, as the combination of remote access capability and authenticated privilege escalation could enable attackers to manipulate operational data or gain deeper system access. This aligns with attack patterns documented in the MITRE ATT&CK framework under privilege escalation and defense evasion techniques.
Security mitigations for this vulnerability require immediate patching of Advantech WebAccess installations to version 8.1_20160519 or later, which addresses the flawed ActiveX control implementation. Organizations should also implement network segmentation to limit access to these systems, enforce strict authentication controls, and monitor for unusual access patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper COM component security configuration and highlights the risks associated with legacy ActiveX controls in modern industrial environments. According to CWE classification, this vulnerability relates to CWE-264, which covers permissions, privileges, and access control issues, and represents a failure to properly implement security boundaries in component-based applications. System administrators should also consider implementing additional monitoring for COM object activation and registry modifications related to ActiveX controls to detect potential exploitation attempts.