The Daikin Security Gateway 214 suffers from a critical security vulnerability in its remote password reset API endpoint. This vulnerability is an Insecure Direct Object Reference (IDOR) flaw that allows an unauthenticated attacker to send a specially crafted POST request to the password reset endpoint without any authentication or authorization checks. Exploiting this flaw resets the system credentials to the default username and password combination (Daikin:Daikin). The Security Gateway acts as an intermediary device that enables iTM and LC8 controllers to communicate with the Daikin Cloud Service by transforming HTTP reports into HTTPS and forwarding them via the router. By resetting the password remotely, attackers can gain unauthorized access to the gateway, potentially compromising the connected HVAC controllers and the broader network environment. The exploit code is implemented as a Bash script that sends a POST request with a minimal payload to the vulnerable endpoint and parses the JSON response to confirm successful exploitation. The vulnerability affects the application version 100 and firmware version 214 of the Daikin Security Gateway. No official patches or fixes have been published yet, and no known exploits have been observed in the wild as of the publication date. The flaw allows attackers to bypass authentication entirely, making exploitation straightforward if the device is reachable over the network. This vulnerability poses a significant risk to the confidentiality, integrity, and availability of the affected systems and connected infrastructure.

For European organizations, the impact of this vulnerability can be substantial, especially for those relying on Daikin HVAC systems integrated with the Security Gateway 214. Unauthorized access to the gateway could allow attackers to manipulate HVAC controls, disrupt building climate management, or pivot to other internal network resources, potentially leading to operational downtime or safety hazards. Confidential information related to building management systems could be exposed or altered. Given that HVAC systems are often critical infrastructure components in commercial buildings, hospitals, data centers, and industrial facilities, exploitation could result in physical discomfort, damage to sensitive equipment, or interruption of critical services. Additionally, compromised gateways could serve as footholds for broader network intrusions or lateral movement within enterprise environments. The ease of exploitation without authentication increases the risk of automated attacks or mass scanning campaigns targeting exposed devices. Organizations with remote or internet-facing Security Gateways are particularly vulnerable. The lack of patches and the default credential reset behavior exacerbate the risk, making timely mitigation essential to prevent unauthorized access and potential cascading effects on operational technology environments.

1. Network Segmentation: Immediately isolate Daikin Security Gateway devices from direct internet exposure by placing them behind firewalls or within segmented network zones accessible only to trusted management systems. 2. Access Control: Implement strict access control lists (ACLs) to restrict which IP addresses or subnets can communicate with the gateway's management interfaces, effectively blocking unauthorized remote access attempts. 3. Monitor and Detect: Deploy network monitoring and intrusion detection systems to identify unusual POST requests to the /api/settings/password/reset endpoint or other anomalous traffic patterns targeting the gateway. 4. Change Default Credentials: After any password reset event, promptly change the default credentials to a strong, unique password to prevent unauthorized reuse. 5. Vendor Engagement: Engage with Daikin support channels to obtain official patches or firmware updates addressing this vulnerability as soon as they become available. 6. Incident Response Preparedness: Prepare incident response plans specifically for HVAC and IoT device compromises, including procedures for rapid credential resets and device isolation. 7. Disable Unused Services: If possible, disable the password reset API endpoint or restrict its usage to authenticated and authorized users only, potentially through custom firewall rules or device configuration. 8. Physical Security: Ensure physical security controls are in place to prevent local tampering with the gateway devices. These measures go beyond generic advice by focusing on network-level controls, monitoring, and operational procedures tailored to the specific vulnerability and device context.