CVE-2025-34081 is a medium-severity vulnerability affecting Contec Co.,Ltd.'s CONPROSYS HMI System (CHS) versions prior to 3.7.7. The issue arises from the exposure of a PHP phpinfo() debug page to unauthenticated users. The phpinfo() function in PHP outputs detailed information about the PHP environment, including configuration settings, loaded modules, environment variables, and potentially sensitive data such as paths, server variables, and sometimes credentials or tokens if they are present in environment variables or configuration. Because this debug page is accessible without authentication, any remote attacker can access it and gather sensitive information that could facilitate further attacks, such as identifying software versions, server configurations, or internal network details. This vulnerability is classified under CWE-215 (Insertion of Sensitive Information Into Debugging Code), indicating that sensitive information is unintentionally exposed through debugging features left enabled in production environments. The CVSS 4.0 base score is 6.9, reflecting a medium severity with characteristics including network attack vector, no required privileges, no user interaction, and low impact on confidentiality only. There are no known exploits in the wild at the time of publication, and no patches are linked, suggesting that remediation may require upgrading to version 3.7.7 or later once available or applying vendor guidance. The vulnerability affects all versions before 3.7.7, with no specific minor versions detailed. The exposure of such debug information can aid attackers in reconnaissance and crafting targeted attacks against the HMI system or the underlying infrastructure.

For European organizations using CONPROSYS HMI Systems, this vulnerability poses a risk primarily to confidentiality. Attackers can remotely access detailed system information without authentication, which can be leveraged to identify further vulnerabilities or misconfigurations. In industrial environments where HMI systems are critical for monitoring and controlling manufacturing or infrastructure processes, such information disclosure can lead to increased risk of targeted attacks, including sabotage, espionage, or disruption. While the vulnerability itself does not allow direct control or data modification, the sensitive information exposure can facilitate lateral movement or privilege escalation attempts. Given the critical role of HMI systems in sectors like manufacturing, energy, and utilities, European organizations in these industries could face operational risks if attackers exploit this vulnerability as a stepping stone. The lack of required authentication and user interaction increases the ease of exploitation, raising concerns for organizations with internet-facing or poorly segmented HMI systems.

1. Immediate mitigation should include restricting access to the phpinfo() debug page by implementing network-level controls such as firewall rules or VPN access to limit exposure only to trusted administrators. 2. Disable or remove any debug or diagnostic pages like phpinfo() in production environments to prevent accidental information leakage. 3. Upgrade the CONPROSYS HMI System to version 3.7.7 or later once the vendor releases a patch addressing this vulnerability. 4. Conduct thorough audits of the HMI system configuration to ensure no other debug features or sensitive information exposures exist. 5. Implement network segmentation to isolate HMI systems from general IT networks and the internet, reducing the attack surface. 6. Monitor access logs for unusual or unauthorized requests to debug pages or system endpoints. 7. Educate operational technology (OT) and IT teams about the risks of leaving debugging features enabled in production and enforce secure deployment practices.