CVE-2021-45229 in Airflow
Summary
by MITRE • 02/25/2022
It was discovered that the "Trigger DAG with config" screen was susceptible to XSS attacks via the `origin` query argument. This issue affects Apache Airflow versions 2.2.3 and below.
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Analysis
by VulDB Data Team • 02/28/2022
The vulnerability identified as CVE-2021-45229 represents a cross-site scripting weakness in Apache Airflow's web interface that specifically impacts the "Trigger DAG with config" functionality. This security flaw exists within the application's handling of the `origin` query parameter, which is processed during the DAG triggering process. The issue affects all versions of Apache Airflow up to and including version 2.2.3, making it a significant concern for organizations that have not yet upgraded their deployment to newer releases. The vulnerability stems from insufficient input validation and sanitization of user-supplied parameters that are directly reflected in the web application's response without proper encoding or filtering mechanisms.
The technical implementation of this vulnerability occurs when a malicious user crafts a specially formatted URL containing a crafted payload within the `origin` query argument. When the victim navigates to this malicious URL while authenticated to the Airflow web interface, the application fails to properly sanitize the input before rendering it in the browser context. This allows an attacker to inject arbitrary JavaScript code that executes within the victim's browser session, potentially leading to session hijacking, credential theft, or further exploitation of the compromised user's privileges. The vulnerability is classified as a reflected cross-site scripting issue under CWE-79, which specifically addresses the improper handling of untrusted data in web applications. This weakness falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as it enables the execution of malicious JavaScript code within the context of the vulnerable application.
The operational impact of this vulnerability extends beyond simple script execution as it can be leveraged to escalate privileges within the Airflow environment. Since Airflow typically operates with administrative capabilities for DAG management and workflow execution, an attacker who successfully exploits this XSS vulnerability can potentially manipulate workflows, access sensitive configuration data, or even trigger unauthorized DAG executions. The attack surface is particularly concerning for organizations that use Airflow as part of their data processing pipelines, as it could lead to data manipulation or disruption of critical business processes. The vulnerability is especially dangerous when considering that Airflow often runs in enterprise environments where users may have elevated permissions, and the reflected nature of the attack means that the malicious payload does not need to be stored on the server. Organizations using older versions of Airflow without proper input validation are at risk of having their workflow automation systems compromised through this vector.
Mitigation strategies for CVE-2021-45229 primarily involve upgrading to Apache Airflow version 2.2.4 or later, where the vulnerability has been addressed through proper input sanitization of the `origin` parameter. Organizations should also implement additional security controls such as web application firewalls that can detect and block suspicious query parameters, and conduct thorough input validation across all user-supplied data in web applications. The implementation of Content Security Policy headers can provide an additional layer of protection against XSS attacks by restricting the sources from which scripts can be loaded and executed within the application context. Security teams should also consider implementing regular security scanning of their Airflow installations to identify potential vulnerabilities and ensure that all components are running supported versions. Additionally, user education and awareness programs should emphasize the importance of not clicking on suspicious links, particularly in environments where Airflow is used for critical data processing tasks. The fix implemented in newer versions addresses the root cause by ensuring that all user-supplied input is properly escaped or filtered before being rendered in the web interface, preventing the execution of malicious scripts that could otherwise be injected through the vulnerable parameter handling mechanism.