Apache Airflow is an open-source tool used by thousands of companies to programmatically author, schedule, and monitor workflows. However, a critical vulnerability has been discovered – CVE-2023-40712 – that can expose sensitive data to authenticated users.

In this post, I’ll break down what the vulnerability is, how it can be exploited in simple terms, show code snippets that illustrate this, and share official references for further reading.

What is CVE-2023-40712?

If you use Airflow before version 2.7.1, your instance is vulnerable. The problem is that sensitive configuration values (“secrets”) that are supposed to be hidden (masked) in the Airflow UI could be revealed.

What can happen?

- Authenticated users could craft a special URL and see plain text secrets (API keys, passwords, tokens) that the UI is supposed to mask.

How the Exploit Works

Normally, secret values (like api_key) show up in the UI as <b></b>**. But due to a flaw, if you craft the right URL, Airflow ignores the “mask” and returns the raw secret in the response.

Exploit Steps

1. Login to Airflow as a user with access to a DAG/task.

Example Snippet

Suppose you have a DAG named daily_data_pipeline and a task called fetch_secrets_task.

The standard URL would look like this

http://your-airflow-host:808/taskinstance/list/?dag_id=daily_data_pipeline

If you click on a task and inspect the details, you see

"api_key": "**"

But if you tinker with the API endpoint (in these vulnerable versions), such as

http://your-airflow-host:808/api/v1/dags/daily_data_pipeline/dagRuns/<dag_run_id>/taskInstances/fetch_secrets_task

Or you request the conf/resource with something like

curl -H "Authorization: Basic <base64_credentials>" \
     "http://your-airflow-host:808/api/v1/dags/daily_data_pipeline/dagRuns/<dag_run_id>/taskInstances/fetch_secrets_task"

In the vulnerable versions, the response could include

{
  "conf": {
    "api_key": "supersecretapikeyvalue",  // <-- UNMASKED!
    "some_other_value": "xxxxxxx"
  }
}

Why Does This Happen?

Airflow masks secrets on the frontend only. If you directly request details via the API or through a tweaked URL, the backend doesn’t always apply masking – until 2.7.1 fixed it.

Impact: Who Should Worry?

- Companies using Airflow on shared networks: Any person with a valid login could harvest secrets used by other workflows.
- Sensitive Environments: If your DAGs touch production APIs, databases, or cloud resources, secrets leak could allow privilege escalation or even lateral movement inside your infrastructure.

How to Fix

Immediate solution:
Upgrade to Airflow version 2.7.1 or later. The development team patched the backend so secrets remain masked everywhere, regardless of the request path.

Upgrade Steps (example with pip)

# If installed via pip
pip install --upgrade apache-airflow
# Or specify version
pip install apache-airflow==2.7.1

*Make sure to restart Airflow components (webserver, scheduler, workers) after upgrading.*

References

- Apache Airflow Security Advisory: CVE-2023-40712
- Official Apache Airflow changelog
- CVE-2023-40712 at NVD

Stay safe and keep those secrets secret!

If you have questions or want a walkthrough of the patch, feel free to reply below. And remember: always patch your open-source tools quickly!


*This guide is exclusive and written in easy-to-understand American English for quick awareness among Apache Airflow users.*

Timeline

Published on: 09/12/2023 12:15:08 UTC
Last modified on: 09/13/2023 03:50:38 UTC