External risk intelligence

Apache Airflow Experimental API Authentication Bypass

CVE advisoryKnown Exploit

CVE-2020-13927

The Apache Airflow Experimental API may allow unauthorized access due to a previous default setting. This could lead to unauthorized data access or system control. Organizations should verify their Airflow configurations to mitigate this risk.

4Halo Surface Signal

Missing Authentication

Apache Airflow

before 1.10.11

External exposure likelihood

Halo Surface Signal score for CVE-2020-13927

Apache Airflow is commonly deployed as a web-based service for workflow orchestration. While the experimental API in question was intended for internal use, such management and automation interfaces are frequently exposed to the network to facilitate distributed integrations, making them plausibly reachable in many deployment environments.

Horizon Alert

Summary of the vulnerability and why it matters

The Apache Airflow Experimental API can be accessed without authentication, posing a security risk. This flaw allows unauthorized access to the API. The potential impact includes unauthorized data access, modification, or system control.

  • Vulnerable API endpoint
  • Lack of API authentication
  • Unauthorized system access

Attack Path

How an attacker could exploit the issue

The Experimental API in Apache Airflow previously allowed all API requests without authentication. This default setting posed a security risk, as organizations might not have been aware of the exposure. Attackers could exploit this by sending unauthenticated requests to the API.

  • Exposure condition: Unauthenticated API access is enabled.
  • Attacker starting point: Network access to the API.
  • Trigger and result: Attacker sends requests, gaining unauthorized access.

Live Threat

Current exploitation, exposure, and threat context

The Apache Airflow Experimental API historically allowed all API requests without authentication, creating a security risk if this default was not adjusted. While newer installations default to denying all requests, existing deployments require manual configuration changes to remediate this vulnerability. Attackers could exploit this to gain unauthorized access to sensitive data and potentially execute commands. The risk associated with this vulnerability is considered high and warrants immediate attention to implement the necessary security configurations.

  • Attackers with no special skills.
  • No authentication needed to access.
  • High business risk; treat as urgent.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

The organization's systems may be at risk due to an authentication bypass vulnerability in Apache Airflow's Experimental API. This vulnerability allows unauthenticated API requests, potentially exposing sensitive operations and data. The risk increases for organizations that have not updated their Airflow configurations.

  • Find Airflow assets with exposed experimental APIs.
  • Restrict access to the experimental API.
  • Apply configuration changes and verify.
  • Monitor for related activity.

Frequently asked questions

What is Apache Airflow and its Experimental API?

Apache Airflow is an open-source platform for programmatically authoring, scheduling, and monitoring workflows. Its Experimental API, prior to version 1.10.11, allowed all API requests without authentication by default, posing significant security risks.

What is CVE-2020-13927 and its weakness class?

CVE-2020-13927 is an authentication bypass vulnerability in Apache Airflow's Experimental API. It is classified under CWE-306, Missing Authentication for Critical Function, and CWE-1188, Insecure Default Initialization of Resource.

How can CVE-2020-13927 be exploited?

Attackers can exploit CVE-2020-13927 by sending unauthenticated HTTP requests to the Experimental API endpoints over a network. This can lead to unauthorized access, triggering DAGs, accessing sensitive information, and potentially achieving remote code execution on the underlying system.

What is the relevance of CVE-2020-13927 to organizations?

This vulnerability is highly relevant as it allows unauthenticated remote attackers to access sensitive data and execute arbitrary code on Airflow systems. CISA has included it in its Known Exploited Vulnerabilities catalog, emphasizing the need for immediate attention.

What steps should be taken to respond to CVE-2020-13927?

Organizations should upgrade Apache Airflow to version 1.10.11 or later. For existing installations, manually configure the `[api]auth_backend` to `airflow.api.auth.backend.deny_all`, restrict network access to Airflow instances, and monitor logs for suspicious activity.

References