CVE-2025-0658 is a vulnerability identified in Automated Logic and Carrier's Zone Controllers, which are devices used in building automation systems to control HVAC and other environmental parameters. The vulnerability arises from improper input validation (CWE-20) in the handling of BACnet protocol packets. Specifically, the device can be forced to crash and enter a fault state upon receiving a maliciously crafted BACnet packet. After the device is reset, a second malicious packet can cause the device to become permanently unresponsive until a manual power cycle is performed, effectively causing a denial of service. The vulnerability is remotely exploitable without any authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The CVSS v4.0 score of 8.7 reflects the high impact on availability (VA:H) with no impact on confidentiality or integrity. The scope is unchanged, meaning the vulnerability affects only the vulnerable component. No patches or known exploits are currently available, but the risk is significant given the critical role these controllers play in managing building environments. The lack of authentication and ease of exploitation make this vulnerability a serious concern for operational continuity in facilities using these devices.

For European organizations, the primary impact is a denial of service on building automation systems that rely on Automated Logic Zone Controllers. This can disrupt HVAC operations, leading to uncomfortable or unsafe environmental conditions, potential damage to sensitive equipment, and increased energy costs. Critical infrastructure facilities such as hospitals, data centers, and manufacturing plants could face operational disruptions. The need for manual power cycling to recover devices increases operational overhead and response time, potentially extending downtime. Additionally, widespread exploitation could lead to cascading failures in integrated building management systems. The lack of confidentiality or integrity impact limits data breach concerns, but availability degradation alone can have significant safety and financial consequences. Organizations in Europe with extensive BACnet deployments or reliance on Automated Logic products are particularly vulnerable.

1. Implement strict network segmentation to isolate BACnet traffic and limit exposure of Zone Controllers to untrusted networks. 2. Deploy network monitoring and intrusion detection systems capable of analyzing BACnet protocol traffic to detect anomalous or malformed packets indicative of exploitation attempts. 3. Establish incident response procedures to quickly identify and manually power cycle affected devices if they become unresponsive. 4. Engage with the vendor (Automated Logic/Carrier) for updates on patches or firmware upgrades addressing this vulnerability and apply them promptly once available. 5. Restrict access to BACnet devices using firewall rules and VPNs to trusted personnel and systems only. 6. Conduct regular security assessments and penetration testing focused on building automation systems to identify and remediate similar vulnerabilities. 7. Maintain detailed asset inventories to ensure all Zone Controllers are accounted for and monitored. 8. Train operational technology (OT) staff on recognizing symptoms of this vulnerability exploitation and appropriate response actions.