CVE-2018-8845 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, a heap-based buffer overflow vulnerability has been identified, which may allow an attacker to execute arbitrary code.
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Analysis
by VulDB Data Team • 02/05/2020
The CVE-2018-8845 vulnerability represents a critical heap-based buffer overflow flaw affecting multiple Advantech WebAccess products including the main WebAccess platform, WebAccess Dashboard, WebAccess Scada Node, and WebAccess/NMS components. This vulnerability exists in versions prior to the specified patches, creating a significant attack surface for malicious actors targeting industrial control systems and SCADA environments. The flaw stems from improper input validation within the software's memory management mechanisms, specifically when processing user-supplied data that exceeds allocated buffer boundaries. The vulnerability is particularly concerning in industrial environments where these systems are commonly deployed for critical infrastructure monitoring and control.
The technical implementation of this buffer overflow occurs within the heap memory management subsystem of Advantech WebAccess applications, where insufficient bounds checking allows attackers to write data beyond the allocated memory space. This condition enables arbitrary code execution through carefully crafted input sequences that overwrite critical memory locations including return addresses and function pointers. The vulnerability operates at the application layer and can be exploited remotely, making it particularly dangerous for networked industrial systems. According to CWE-121, this represents a classic heap-based buffer overflow vulnerability where the flaw allows for stack smashing and potentially full system compromise. The attack vector typically involves sending malformed data to the affected WebAccess services, which then processes this input without proper validation, leading to memory corruption that can be leveraged for privilege escalation.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise and potential disruption of critical industrial processes. In SCADA environments where WebAccess systems control industrial equipment and processes, successful exploitation could result in unauthorized access to operational controls, data manipulation, or complete system outages. The vulnerability's presence in multiple product lines including the dashboard and node components means that attackers can potentially target various points within a single industrial network infrastructure. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where adversaries can leverage the executed code to establish persistence and further compromise networked industrial systems. The attack surface is particularly dangerous in environments where these systems are not properly segmented from corporate networks, as the vulnerability could enable lateral movement and escalation of privileges.
Mitigation strategies for CVE-2018-8845 should prioritize immediate patching of all affected Advantech WebAccess products to the latest versions that contain the necessary memory validation fixes. Organizations should implement network segmentation to isolate WebAccess systems from general corporate networks, reducing the attack surface available to potential adversaries. Input validation controls should be strengthened at all network boundaries where these systems are accessed, including implementing strict data filtering and monitoring for anomalous traffic patterns. Regular security assessments of industrial control systems should include vulnerability scanning specifically targeting known heap overflow vulnerabilities in SCADA platforms. Network monitoring solutions should be configured to detect unusual memory access patterns and potential exploitation attempts. System administrators should also consider implementing application whitelisting policies to restrict execution of unauthorized code, and maintain detailed audit logs of all system access and modifications for forensic analysis. The vulnerability demonstrates the critical importance of keeping industrial control system software updated and following secure coding practices to prevent memory corruption attacks that could have severe consequences in operational technology environments.