CVE-2019-6550 in WebAccess SCADA
Summary
by MITRE
Advantech WebAccess/SCADA, Versions 8.3.5 and prior. Multiple stack-based buffer overflow vulnerabilities, caused by a lack of proper validation of the length of user-supplied data, may allow remote code execution.
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Analysis
by VulDB Data Team • 08/27/2023
The vulnerability identified as CVE-2019-6550 affects Advantech WebAccess/SCADA software versions 8.3.5 and earlier, representing a critical security flaw that exposes industrial control systems to remote exploitation. This issue manifests as multiple stack-based buffer overflow conditions within the software's handling of user-supplied data, creating a significant attack surface for malicious actors targeting industrial environments. The vulnerability resides in the application's failure to properly validate input length parameters, allowing attackers to craft malicious payloads that can overwrite adjacent memory locations in the program's stack.
The technical implementation of this vulnerability stems from inadequate bounds checking mechanisms within the WebAccess/SCADA application's data processing routines. When the software receives input from network connections or file operations, it does not sufficiently verify that the data length conforms to expected parameters before copying it into fixed-size buffer structures. This fundamental flaw creates opportunities for attackers to overflow the allocated stack space and potentially overwrite return addresses, function pointers, or other critical control data. The nature of stack-based buffer overflows makes this particularly dangerous as it can lead to arbitrary code execution with the privileges of the running process, often corresponding to system-level access within industrial control environments.
The operational impact of CVE-2019-6550 extends beyond typical network security concerns into the realm of industrial control system integrity and operational continuity. Organizations utilizing Advantech WebAccess/SCADA systems face potential risks including unauthorized access to critical infrastructure, data manipulation, system compromise, and possible disruption of industrial processes. These vulnerabilities are particularly concerning in environments where operational technology (OT) systems control physical processes such as manufacturing, power generation, or water treatment facilities. The remote exploitation capability means that attackers can potentially compromise these systems from outside the organization's network perimeter, making traditional network segmentation less effective as a protective measure.
Security professionals should consider this vulnerability in the context of the MITRE ATT&CK framework, particularly under the techniques related to remote code execution and privilege escalation. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental weakness in software design that frequently leads to exploitable conditions. Organizations should implement immediate mitigations including applying the vendor-provided patches, restricting network access to affected systems, implementing network segmentation, and monitoring for suspicious network activity. Additionally, the vulnerability demonstrates the importance of secure coding practices and input validation as outlined in industry standards such as the OWASP Top Ten and NIST Cybersecurity Framework, emphasizing that proper bounds checking and validation should be integral components of all software development processes in critical infrastructure environments.