CVE-2021-41104 : Exploit Details and Defense Strategies

ESPHome is a system to control the ESP8266/ESP32, but a vulnerability in the

web_server

component allows for OTA updates without proper authentication. Learn more about this CVE below.

Understanding CVE-2021-41104

What is CVE-2021-41104?

ESPHome versions prior to 2021.9.2 are susceptible to a critical issue where the

web_server

module permits over-the-air updates without validating user-defined basic authentication credentials.

The Impact of CVE-2021-41104

This vulnerability has a CVSS v3.1 base score of 7.5, indicating a high severity issue that could compromise the integrity of affected systems.

Technical Details of CVE-2021-41104

Vulnerability Description

An issue in the

web_server

allows for unauthorized OTA updates without checking user-defined basic authentication credentials.

Affected Systems and Versions

Product: esphome
Vendor: esphome
Vulnerable Versions: < 2021.9.2

Exploitation Mechanism

Attack Complexity: Low
Attack Vector: Network
Integrity Impact: High

Mitigation and Prevention

Immediate Steps to Take

Update ESPHome to version 2021.9.2 or newer to prevent exploitation.
Disable or remove the

web_server

if not needed.

Long-Term Security Practices

Regularly review and update configurations related to authentication mechanisms.
Monitor security advisories and apply patches promptly.
Conduct security assessments to identify and remediate vulnerabilities.

Patching and Updates

The issue is resolved in version 2021.9.2 of ESPHome, so ensure timely updating to mitigate the risk of unauthorized OTA updates.