CVE-2017-12717 in WebAccess
Summary
by MITRE
An Uncontrolled Search Path Element issue was discovered in Advantech WebAccess versions prior to V8.2_20170817. A maliciously crafted dll file placed earlier in the search path may allow an attacker to execute code within the context of the application.
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Analysis
by VulDB Data Team • 11/12/2019
The vulnerability identified as CVE-2017-12717 represents a critical uncontrolled search path element flaw affecting Advantech WebAccess software versions prior to V8.2_20170817. This type of vulnerability falls under the CWE-427 category, which specifically addresses uncontrolled search path elements that can lead to privilege escalation and arbitrary code execution. The issue stems from the application's failure to properly validate the search path used when loading dynamic link libraries, creating an environment where malicious actors can manipulate the software's execution flow through strategic placement of crafted dll files.
The technical implementation of this vulnerability exploits the Windows dynamic link library loading mechanism by placing malicious dll files in directories that are searched before the legitimate application directories. This occurs because the application's search path is not properly constrained or sanitized, allowing attackers to position their malicious payload in a location that gets prioritized during the dll loading process. When the application attempts to load a required library, it inadvertently executes the attacker-controlled code, effectively providing a code execution vector within the application's security context. The vulnerability is particularly dangerous because it operates at the system level, leveraging the trust model that applications place in their runtime environments.
From an operational perspective, this vulnerability presents significant risks to industrial control systems and automation environments where Advantech WebAccess is deployed. The attack surface is particularly concerning in environments where physical security is limited, as an attacker could potentially compromise entire industrial networks through a single vulnerable application instance. The impact extends beyond simple code execution to include potential privilege escalation, data exfiltration, and system compromise. Organizations using these systems face the risk of operational technology disruption, safety system compromise, and potential regulatory violations, especially in critical infrastructure sectors where such vulnerabilities can have cascading effects on overall system integrity.
The mitigation strategy for CVE-2017-12717 involves immediate application of the vendor-provided patch to Advantech WebAccess versions prior to V8.2_20170817, which addresses the uncontrolled search path issue through proper path validation and sanitization. System administrators should also implement additional security measures including application whitelisting, restricted file permissions, and monitoring for suspicious dll loading activities. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter usage and T1068 for exploit for privilege escalation, making it a significant concern for security operations teams monitoring for lateral movement and privilege escalation attempts. Organizations should also conduct comprehensive vulnerability assessments to identify other potentially affected systems and implement network segmentation to limit the potential impact of such attacks, as this vulnerability could serve as an initial access vector in broader attack campaigns targeting industrial control systems.