CVE-2025-34243 is a SQL injection vulnerability classified under CWE-89 that affects Advantech's WebAccess/VPN product versions prior to 1.1.5. The vulnerability resides in the AjaxFwRulesController.ajaxNetworkFwRulesAction() method, which processes datatable search parameters without properly neutralizing special SQL elements. This improper input sanitization allows an authenticated user with low privileges (observer role) to inject arbitrary SQL commands. The attack vector is network-based and does not require user interaction or elevated privileges beyond observer access, making it relatively easy to exploit. Successful exploitation can lead to unauthorized disclosure of sensitive database contents, potentially exposing configuration details, user data, or other critical information stored in the backend database. The CVSS 4.0 base score is 5.3, reflecting medium severity due to the limited privileges required and the impact primarily on confidentiality with limited integrity or availability effects. No patches or exploits are currently publicly available, but the vulnerability's presence in a VPN and web access product used in industrial and enterprise environments raises concerns about potential data leakage and reconnaissance by attackers. The vulnerability highlights the need for secure coding practices, especially in input validation and sanitization in web applications handling sensitive network and firewall rules.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive network and firewall configuration data, which may facilitate further attacks such as lateral movement or privilege escalation. Industrial sectors relying on Advantech WebAccess/VPN for remote monitoring and control, including manufacturing, energy, and critical infrastructure, could face increased risk of espionage or sabotage. The compromise of confidentiality could undermine trust in operational technology environments and lead to regulatory compliance issues under GDPR if personal or sensitive data is exposed. Although the vulnerability does not directly enable denial of service or code execution, the information disclosure could be leveraged by threat actors to plan more damaging attacks. The medium severity rating suggests that while the immediate impact is moderate, the strategic value of the exposed data could be significant in targeted attacks against European critical infrastructure and industrial enterprises.

Organizations should immediately upgrade Advantech WebAccess/VPN to version 1.1.5 or later where the vulnerability is fixed. If upgrading is not immediately possible, implement strict input validation and sanitization on the server side to neutralize special SQL characters in datatable search parameters. Restrict observer user privileges further to limit access to sensitive functions and monitor logs for unusual query patterns indicative of SQL injection attempts. Employ Web Application Firewalls (WAFs) with rules tailored to detect and block SQL injection payloads targeting the AjaxFwRulesController.ajaxNetworkFwRulesAction() endpoint. Conduct regular security assessments and code reviews of custom integrations with the product. Additionally, network segmentation should be enforced to isolate the VPN management interface from broader enterprise networks to reduce exposure. Finally, ensure incident response plans include procedures for detecting and responding to SQL injection attacks.