Taiwan-based industrial automation company Advantech has updated its WebAccess product to address a couple of vulnerabilities that could allow attackers to execute arbitrary code on affected systems.
WebAccess is a browser-based software package for human-machine interfaces (HMI) and supervisory control and data acquisition (SCADA) systems. The product, formerly known as BroadWin WebAccess, is used worldwide in the commercial facilities, energy, critical manufacturing and government facilities sectors.
According to ICS-CERT, Zhou Yu of Acorn Network Security discovered that Advantech WebAccess is plagued by two medium severity vulnerabilities that can be exploited by a local attacker.
One of them, tracked as CVE-2016-4525, is related to the use of ActiveX controls, which are meant to be restricted, but are marked as “safe-for-scripting.” These types of flaws can allow an attacker to use potentially dangerous functionality via the web page that accesses the ActiveX control, which could lead to the execution of unauthorized code or commands. Microsoft provides a detailed description on how to ensure safe scripting for ActiveX controls.
The second flaw, identified as CVE-2016-4528, allows an attacker to trigger a buffer overflow by using a specially crafted DLL file. Buffer overflows usually lead to crashes or arbitrary code execution.
“These vulnerabilities are not exploitable remotely and cannot be exploited without user interaction. The exploit is only triggered when a local user runs the vulnerable application, which in certain scenarios can cause it to load a DLL file from an untrusted source,” ICS-CERT said in its advisory.
Advantech patched the vulnerabilities with the release of WebAccess 8.1_20160519, and Zhou Yu has confirmed that the update resolves the issues he discovered.
This is the second time Advantech patches WebAccess vulnerabilities this year. In January, ICS-CERT reported that the company had released an update to address more than a dozen flaws identified by several researchers. The list included cross-site scripting (XSS), unrestricted file upload, SQL injection, path traversal, improper access control, insecure storage of information, and memory corruption issues.
Advantech attempted to fix the vulnerabilities with the release of WebAccess 8.1, but the Zero Day Initiative (ZDI) revealed in February that some of the flaws had not been patched properly.
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