CVE-2024-5540 is a reflective cross-site scripting (XSS) vulnerability classified under CWE-79, found in Automated Logic's WebCTRL and Carrier i-Vu building management systems prior to version 8.0. The vulnerability resides in the login panels where user-supplied input is improperly neutralized during web page generation, allowing malicious actors to inject and execute arbitrary scripts in the context of the victim's browser. The attack vector is network-based, requiring no authentication or user interaction, which increases the risk of automated exploitation or drive-by attacks. The vulnerability compromises the confidentiality and integrity of client sessions by potentially stealing cookies, session tokens, or performing actions on behalf of the user. Although no known exploits have been reported in the wild, the presence of this vulnerability in critical building automation systems poses a risk to operational security. The CVSS 4.0 score of 6.9 reflects medium severity, considering the ease of exploitation and potential impact. The vulnerability affects all versions prior to 8.0, but no specific patch links are currently provided. Automated Logic WebCTRL and Carrier i-Vu are widely used in commercial and industrial buildings for HVAC and energy management, making this vulnerability relevant to organizations relying on these systems for facility operations. The improper input sanitization during web page generation is a common web application security flaw that can be mitigated by proper encoding and validation of user inputs.

For European organizations, this vulnerability could lead to client-side compromise of users accessing the WebCTRL or Carrier i-Vu login panels. Attackers could steal authentication tokens or perform unauthorized actions within the user's session, potentially leading to unauthorized access to building management controls or sensitive operational data. This could disrupt building operations, impact energy management, or cause safety concerns if attackers manipulate control systems indirectly via compromised sessions. The impact is particularly significant for critical infrastructure, commercial real estate, and industrial facilities that depend on these systems for environmental controls. Additionally, the breach of user credentials or session hijacking could facilitate further lateral movement within corporate networks. The vulnerability's network accessibility and lack of required privileges increase the risk of widespread exploitation if attackers target exposed management interfaces. European organizations must consider the potential regulatory implications under GDPR if personal data or operational data is compromised through this vulnerability.

1. Upgrade Automated Logic WebCTRL and Carrier i-Vu to version 8.0 or later once patches are released to address CVE-2024-5540. 2. In the interim, restrict access to the login panels by implementing network segmentation and limiting exposure to trusted networks only. 3. Deploy web application firewalls (WAFs) with rules specifically designed to detect and block XSS payloads targeting the affected login pages. 4. Implement Content Security Policy (CSP) headers to reduce the impact of injected scripts executing in browsers. 5. Conduct regular security assessments and penetration testing focused on web interfaces of building management systems. 6. Educate users and administrators about the risks of phishing and social engineering that could leverage this vulnerability. 7. Monitor logs and network traffic for unusual patterns indicative of attempted XSS exploitation. 8. Apply strict input validation and output encoding on all user-supplied data in custom integrations or extensions of these platforms. 9. Coordinate with vendors for timely updates and security advisories related to this vulnerability.