CVE-2018-8833

Vulnerability

Advantech WebAccess HMI Designer versions 2.1.7.32 and prior contain a heap-based buffer overflow vulnerability (CWE-122) triggered when processing specially crafted .pm3 project files [1]. The flaw resides in the parsing logic of the HMI Designer application, which does not properly validate input data, leading to a write past the allocated heap buffer.

Exploitation

An unauthenticated attacker can exploit this vulnerability remotely by convincing a user to open a malicious .pm3 file (user interaction required) [1]. The CVSS v3 vector string (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L) indicates low attack complexity and no privileges required, but the victim must open the file. No special network position or authentication is needed.

Impact

Successful exploitation allows an attacker to achieve remote code execution on the affected system, potentially gaining the same privileges as the user running the HMI Designer [1]. The impact is limited to low confidentiality, integrity, and availability compromise per the CVSS score.

Mitigation

As of the advisory publication date (April 25, 2018), no patch or fixed version was available. The Cybersecurity and Infrastructure Security Agency (CISA) recommended that users apply defense-in-depth measures and restrict access to trusted .pm3 files [1]. Users should monitor vendor updates for a future fix.