CVE-2021-35936 Explained : Impact and Mitigation

Apache Airflow prior to version 2.1.2 has a vulnerability where the worker or scheduler runs a Flask logging server without authentication, allowing unauthorized access to log files of Directed Acyclic Graph (DAG) jobs.

Understanding CVE-2021-35936

This CVE relates to the lack of authentication on the logging server in Apache Airflow, potentially leading to exposure of sensitive information.

What is CVE-2021-35936?

The issue arises when remote logging is not enabled, allowing the worker or scheduler to operate a logging server without authentication and binding to all interfaces by default, enabling unauthorized parties to read DAG job log files.

The Impact of CVE-2021-35936

The lack of authentication on the logging server poses a significant risk as attackers could access and view sensitive log data of DAG jobs, potentially compromising confidentiality and system integrity.

Technical Details of CVE-2021-35936

This section explains the vulnerability, affected systems, and the exploitation mechanism.

Vulnerability Description

The vulnerability stems from the logging server's default configuration in Apache Airflow versions prior to 2.1.2, where no authentication is required, leading to potential exposure of log files.

Affected Systems and Versions

Apache Airflow versions earlier than 2.1.2 are affected by this vulnerability, specifically impacting instances where remote logging is not utilized.

Exploitation Mechanism

By exploiting the lack of authentication on the logging server, malicious actors can access and retrieve log files of DAG jobs, possibly containing sensitive information.

Mitigation and Prevention

Learn how to address and prevent the CVE-2021-35936 vulnerability in Apache Airflow.

Immediate Steps to Take

Utilize remote logging with secure protocols like GCS, S3, or Elasticsearch to safeguard log data. Avoid exposing additional ports apart from essential ones like the Webserver and Flower ports.

Long-Term Security Practices

Enhance security measures by regularly updating Apache Airflow to the latest version and ensuring proper authentication mechanisms are in place for all logging servers.

Patching and Updates

Stay informed about security patches and updates released by Apache Airflow to address vulnerabilities like CVE-2021-35936 and maintain a secure deployment.