CVE-2016-4528 in WebAccess
Summary
by MITRE
Buffer overflow in Advantech WebAccess before 8.1_20160519 allows local users to cause a denial of service via a crafted DLL file.
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Analysis
by VulDB Data Team • 02/09/2019
The vulnerability identified as CVE-2016-4528 represents a critical buffer overflow flaw within Advantech WebAccess software prior to version 8.1_20160519. This issue affects the industrial automation and building management systems that rely on Advantech's WebAccess platform for remote monitoring and control operations. The vulnerability specifically resides in how the software processes dynamic link library files, creating an exploitable condition that can be leveraged by local attackers to disrupt system operations. The buffer overflow occurs during the loading or execution of maliciously crafted DLL files, which can lead to arbitrary code execution or system instability. This vulnerability is particularly concerning in industrial control environments where system uptime and reliability are paramount for operational continuity.
The technical implementation of this buffer overflow stems from inadequate input validation within the DLL loading mechanism of Advantech WebAccess. When the system encounters a crafted DLL file, it fails to properly bounds-check the data structure before copying it into a fixed-size buffer. This classic programming error allows an attacker to overwrite adjacent memory locations, potentially corrupting critical system data or executing malicious code. The vulnerability is classified as a local privilege escalation issue since it requires local system access to exploit, though the impact can be severe as it can lead to complete system compromise or denial of service conditions. According to CWE standards, this maps to CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite stack data.
The operational impact of CVE-2016-4528 extends beyond simple denial of service scenarios, particularly within industrial environments where WebAccess systems control critical infrastructure operations. When exploited, this vulnerability can cause system crashes, application hangs, or even complete system shutdowns that may result in production downtime and financial losses. The local nature of the attack means that an attacker must already have access to the target system, but this access could be gained through various initial compromise vectors such as credential theft, physical access, or social engineering attacks. In environments where WebAccess systems manage manufacturing processes, building automation, or utility control systems, the potential for cascading failures and operational disruptions is significant. The vulnerability aligns with ATT&CK technique T1059, which covers command and scripting interpreter usage, as exploitation may involve executing malicious code through the compromised system.
Mitigation strategies for CVE-2016-4528 should focus on immediate software updates and system hardening measures. Organizations must upgrade to Advantech WebAccess version 8.1_20160519 or later, which contains the necessary patches to address the buffer overflow condition. Additionally, implementing strict file validation controls and monitoring for unusual DLL loading activities can help detect potential exploitation attempts. System administrators should also enforce least privilege principles to limit local access rights and implement network segmentation to reduce the attack surface. Regular security assessments and vulnerability scanning should be conducted to identify any remaining exposure points, while security monitoring solutions can help detect anomalous behavior indicative of exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date industrial control system software and implementing robust security practices in operational technology environments.