CVE-2023-36543 - Apache Airflow Vulnerability Allows Authenticated Users to Execute Denial of Service Attacks in Versions before 2.6.3

Security researchers have recently identified a vulnerability in Apache Airflow, a popular open-source platform designed to build, schedule and monitor complex data workflows. The vulnerability, registered as CVE-2023-36543, affects all versions of Airflow before 2.6.3. This vulnerability could allow an authenticated user to make the current request hang, causing a denial of service (DoS) condition.

In this post, we will discuss the details of this vulnerability, explain how it can be exploited, and provide recommendations for securing your Apache Airflow instance.

Vulnerability Details

The vulnerability is caused by improper handling of crafted user input, leading to uncontrolled resource consumption in Apache Airflow (versions before 2.6.3). When exploited, an authenticated user could cause the Airflow server to hang, thereby blocking other users from accessing the system or effectively executing a DoS attack.

# Example of crafted input causing hanging request in vulnerable Airflow version
from airflow.models import TaskInstance

ti = TaskInstance(...)
ti(operator='a'*100000, task_id='b', execution_date=..., log.info=...)

db.session.add(ti)
db.session.commit()

The above code snippet demonstrates how an attacker can craft input that will cause a request to hang, effectively rendering the Airflow instance unavailable to other users.

Ability to craft input that causes the server to hang.

Once these prerequisites are met, the attacker can exploit the vulnerability through the following steps:

Craft input that would cause the server to hang (as shown above in the code snippet).

2. Use the authenticated user account to send a request with the crafted input to the vulnerable API endpoint.

Monitor the server for signs of stalling or freezing.

Following these steps will successfully initiate a DoS attack on the vulnerable Apache Airflow instance.

References

You can find more information about this vulnerability and the affected versions in the following sources:

1. Official Apache Airflow GitHub Repository
2. CVE-2023-36543 Details and Information on the MITRE CVE Website
3. National Vulnerability Database (NVD) Entry for CVE-2023-36543

Mitigation

Users running Apache Airflow versions before 2.6.3 should upgrade to a version that is not affected by this vulnerability. Upgrading to a newer, patched version will prevent this issue from being exploited, ensuring that your Airflow instance remains secure and available for your users.

Additionally, follow these best practices

1. Follow the Apache Airflow Security Best Practices documentation to maintain a secure environment.
2. Limit the number of users who have access to your Airflow instance and ensure they follow proper security protocols.

Regularly review and update your Airflow instance as new security updates and patches are released.

By taking these preventive measures and staying informed about potential vulnerabilities, users can continue to benefit from the powerful functionality of Apache Airflow while maintaining a safe and secure environment.

Timeline

Published on: 07/12/2023 10:15:00 UTC
Last modified on: 07/31/2023 17:47:00 UTC