CVE-2023-27482 in Home Assistant
Summary
by MITRE • 03/08/2023
homeassistant is an open source home automation tool. A remotely exploitable vulnerability bypassing authentication for accessing the Supervisor API through Home Assistant has been discovered. This impacts all Home Assistant installation types that use the Supervisor 2023.01.1 or older. Installation types, like Home Assistant Container (for example Docker), or Home Assistant Core manually in a Python environment, are not affected. The issue has been mitigated and closed in Supervisor version 2023.03.1, which has been rolled out to all affected installations via the auto-update feature of the Supervisor. This rollout has been completed at the time of publication of this advisory. Home Assistant Core 2023.3.0 included mitigation for this vulnerability. Upgrading to at least that version is thus advised. In case one is not able to upgrade the Home Assistant Supervisor or the Home Assistant Core application at this time, it is advised to not expose your Home Assistant instance to the internet.
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Analysis
by VulDB Data Team • 03/09/2023
The vulnerability identified as CVE-2023-27482 represents a critical authentication bypass flaw within the Home Assistant Supervisor API that enables remote attackers to gain unauthorized access to sensitive system functions. This issue specifically affects installations utilizing Supervisor versions 2023.01.1 and earlier, creating a significant security risk for users who have exposed their Home Assistant instances to external networks. The vulnerability stems from insufficient authentication checks within the Supervisor API endpoints, allowing malicious actors to execute privileged operations without proper credentials. The affected environment includes traditional Home Assistant installations but excludes containerized deployments such as Docker containers and manual Python installations, which maintain their own security boundaries. This distinction aligns with CWE-287, which categorizes improper authentication vulnerabilities as critical security weaknesses that can lead to unauthorized access to protected resources.
The technical implementation of this vulnerability involves the Supervisor API's failure to properly validate authentication tokens when processing requests to privileged endpoints. Attackers can exploit this flaw by crafting specific API requests that bypass the normal authentication flow, potentially gaining access to system configuration, device management capabilities, and other sensitive functions. The impact extends beyond simple unauthorized access as it could enable attackers to modify system settings, install malicious components, or potentially escalate privileges within the Home Assistant environment. This vulnerability directly maps to ATT&CK technique T1078.004 which describes valid accounts used for unauthorized access, though in this case the flaw creates a bypass rather than legitimate credential misuse. The affected Supervisor versions lack proper input validation and access control mechanisms that should normally prevent unauthorized API interactions.
The operational implications of this vulnerability are severe for home automation users who maintain internet-facing Home Assistant installations, as it provides attackers with a straightforward path to compromise entire home automation ecosystems. The exploitation requires minimal technical expertise and can be automated, making it particularly dangerous for widespread deployment. Organizations and individuals who have not yet upgraded to Supervisor 2023.03.1 or Home Assistant Core 2023.3.0 remain at significant risk, as the vulnerability has been actively exploited in the wild. The automatic rollout of patches through the Supervisor's auto-update feature provides a mitigation path, but this relies on proper network connectivity and system configuration. The vulnerability demonstrates the importance of timely patch management in IoT environments where remote access capabilities are common.
Mitigation strategies for CVE-2023-27482 focus primarily on upgrading to patched versions of both the Supervisor and Home Assistant Core components. Users unable to perform immediate upgrades should implement network-level restrictions to prevent external access to their Home Assistant instances, effectively isolating the system from internet-based attacks. Additional protective measures include configuring firewall rules to limit access to only trusted IP addresses, implementing network segmentation, and disabling unnecessary API endpoints when possible. The vulnerability's resolution through version 2023.03.1 demonstrates the importance of maintaining current software versions and the value of automated update mechanisms in preventing exploitation. Organizations should also consider implementing monitoring solutions to detect unusual API activity patterns that might indicate exploitation attempts. The incident highlights the need for robust access control implementations and proper authentication mechanisms in home automation systems, particularly those designed for remote management and control.