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Code Execution, DoS Flaws Patched in Advantech WebAccess

Several serious vulnerabilities have been patched by Taiwan-based industrial automation company Advantech in its WebAccess SCADA software.

Advantech WebAccess is a browser-based software package for human-machine interfaces (HMI) and supervisory control and data acquisition (SCADA) systems. The product has been used mainly in the United States, Europe and East Asia, in sectors such as critical manufacturing, energy, and water and wastewater.

According to an advisory published this week by ICS-CERT, researchers discovered that WebAccess is affected by three types of vulnerabilities, including two remote code execution flaws rated “critical” and one denial-of-service (DoS) bug classified as “high severity.”

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The security holes were reported by researchers to Advantech through Trend Micro’s Zero Day Initiative (ZDI). The company has published two dozen advisories describing each variation of the three vulnerabilities.

According to ZDI, the code execution flaws, tracked as CVE-2019-6552 and CVE-2019-6550, can be exploited by an unauthenticated attacker to execute arbitrary code with administrator privileges. The vulnerabilities exist in different executable files, but they all appear to be related to the same resource in the webvrpcs process.

“The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer,” ZDI’s advisories explain.

As for the DoS flaw, identified as CVE-2019-6554, it affects a file named UninstallWA.exe and the same webvrpcs process. An unauthenticated attacker can exploit the weakness to uninstall the application and create a DoS condition on the system.

The vulnerabilities were reported to Advantech in January and ICS-CERT says they were patched with the release of version 8.4.0 of WebAccess.

Related: Critical Code Execution Flaws Patched in Advantech WebAccess

Related: Several Vulnerabilities Patched in Advantech WebAccess

Related: Advantech WebAccess Flaws Allow Access to Sensitive Data

Related: Advantech Failed to Patch Serious Flaws in SCADA Product

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.