CVE-2023-27482

Remote authentication bypass in Home Assistant Supervisor (pre-2023.03.1)

• CVSS 10.0
• CWE-287 Improper Authentication
• Authentication, Authorization, and Session Management
• Remote

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.

CVE

CVE-2023-27482

CWE

CWE-287 Improper Authentication

CVSS base score

10.0

Published

2023-03-08

OWASP

A07 Identification and Authentication Failures

Orthogonal defect classification

Function

Code defect classification

Incorrect Functionality

Category

Authentication, Authorization, and Session Management

Subcategory

Insecure Authentication Mechanisms

Accessibility scope

Remote

Impact

Unauthorized Access

Fixed by upgrading

Yes

Solution

Update Home Assistant Supervisor to version 2023.03.1 or higher.

from flask import Flask, request

app = Flask(__name__)

@app.route('/supervisor_api', methods=['GET', 'POST'])
def supervisor_api():
    return "Supervisor API Access Granted"

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8123)

from flask import Flask, request, abort

app = Flask(__name__)

@app.before_request
def require_authentication():
    if request.endpoint in ['supervisor_api']:
        auth_token = request.headers.get('Authorization')
        if not auth_token or not is_valid_token(auth_token):
            abort(401)

def is_valid_token(token):
    valid_tokens = ['your_valid_token_here']
    return token in valid_tokens

@app.route('/supervisor_api', methods=['GET', 'POST'])
def supervisor_api():
    return "Supervisor API Access Granted"

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8123)

@misc{vaitp:cve202327482,
  title        = {{Remote authentication bypass in Home Assistant Supervisor (pre-2023.03.1)}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2023},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2023-27482},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2023-27482/}}
}