CVE-2024-31486 identifies a security weakness in Siemens OPUPI0 AMQP/MQTT software versions prior to 5.30, where MQTT client passwords are stored without adequate protection, specifically in cleartext on the device. This vulnerability is categorized under CWE-312, which concerns the cleartext storage of sensitive information. The affected product is used for AMQP and MQTT messaging protocols, commonly employed in industrial automation and IoT environments for device communication. An attacker who gains remote shell access with low privileges or physical access to the device can extract these stored credentials, compromising the confidentiality of MQTT client authentication data. The vulnerability does not affect data integrity or availability directly, nor does it require user interaction to exploit. The CVSS 3.1 base score is 5.3, indicating a medium severity level, with the vector reflecting network attack vector (AV:N), high attack complexity (AC:H), low privileges required (PR:L), no user interaction (UI:N), unchanged scope (S:U), high confidentiality impact (C:H), and no impact on integrity or availability (I:N/A:N). No patches or exploits are currently publicly available, but the risk remains significant due to the sensitive nature of the credentials and the potential for lateral movement or further compromise if credentials are harvested. Siemens recommends upgrading to version 5.30 or later where this issue is resolved. The vulnerability highlights the importance of secure credential storage in embedded and industrial communication devices.

For European organizations, particularly those operating in industrial automation, manufacturing, energy, and critical infrastructure sectors, this vulnerability poses a confidentiality risk. Compromise of MQTT client credentials could allow attackers to impersonate legitimate devices or intercept sensitive messaging traffic, potentially leading to unauthorized access to control systems or data exfiltration. Although the vulnerability requires at least low privilege remote shell or physical access, environments with weak access controls or exposed management interfaces are at higher risk. The impact is primarily on confidentiality, but this could cascade into broader operational risks if attackers leverage stolen credentials for further attacks. Given Siemens' strong presence in European industrial sectors, the vulnerability could affect a wide range of organizations, including utilities, manufacturing plants, and transportation systems. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers often target industrial control systems. The medium severity score reflects a moderate but non-trivial risk that should be addressed promptly to prevent potential compromise and data leakage.

1. Upgrade Siemens OPUPI0 AMQP/MQTT software to version 5.30 or later where the vulnerability is fixed. 2. Restrict remote shell access to trusted administrators only and enforce strong authentication and network segmentation to limit exposure. 3. Implement physical security controls to prevent unauthorized physical access to devices. 4. Where upgrading is not immediately possible, consider encrypting stored credentials at rest using device-level encryption or secure storage modules. 5. Monitor device logs and network traffic for unusual access patterns or credential usage indicative of compromise. 6. Conduct regular security audits and vulnerability assessments on industrial communication devices. 7. Educate operational technology (OT) staff on the risks of credential exposure and best practices for device management. 8. Apply network-level protections such as firewall rules and intrusion detection systems to detect and block unauthorized access attempts to affected devices.