This vulnerability allows injection of arbitrary HTML through the `/projects/upload-example` endpoint of Humansignal's Label Studio, prior to version 1.16.0. Specifically, an attacker can exploit this flaw using a specially crafted `label_config` query parameter in a GET request. By doing so, they can achieve Cross-Site Scripting (XSS) through malicious HTML/JavaScript. While Label Studio implements a Content Security Policy (CSP), it is set to report-only mode, rendering it ineffective against this specific attack.
The root cause of the vulnerability lies in the fact that the upload-example endpoint renders user-provided HTML content without adequate sanitization. This oversight allows attackers to inject and execute arbitrary JavaScript in the browsers of users who visit a maliciously crafted URL. The implications of this vulnerability are significant, as attackers may leverage it to steal sensitive data, hijack user sessions, or execute other malicious actions.
Version 1.16.0 of Label Studio contains a patch addressing this vulnerability. Organizations using affected versions should prioritize the implementation of this patch to mitigate the risks associated with this flaw.
The urgency for defenders is high due to the potential for exploitation. Organizations must implement the necessary updates to their systems to ensure that they are protected from such attacks.
Vulnerability Details
The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')). The CVSS score for this vulnerability is 6.1, indicating a medium severity level. The attack vector is network-based, and the attack complexity is low, requiring no privileges but necessitating user interaction.
Technical Analysis
The root cause of this vulnerability is the lack of proper input sanitization at the upload-example endpoint. Attackers can leverage this flaw by crafting a malicious URL that includes an XML label config with embedded JavaScript. The attack complexity is low, as it does not require any special privileges. The user interaction required means that victims must click on the malicious link for the attack to succeed.
Risk & Impact Analysis
Risk to organizations includes potential theft of sensitive data and session hijacking, which can have serious implications for their operational integrity and user trust. The blast radius is concerning, particularly for users who may unknowingly interact with compromised endpoints. Given the CVSS score and the nature of the vulnerability, organizations should address this vulnerability in their priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of Label Studio prior to 1.16.0 are affected by this vulnerability. Users should upgrade to version 1.16.0 or later to mitigate the risk.
Mitigation & Remediation
Organizations should prioritize patching immediately by updating to Label Studio version 1.16.0, which contains fixes for this vulnerability. For those unable to apply the patch immediately, implement input validation and sanitization for user inputs on the affected endpoint.
Detection Guidance
Monitor logs for unusual requests to the `/projects/upload-example` endpoint, particularly those that include the `label_config` parameter. Look for patterns indicative of XSS attempts, such as the presence of `<script>` tags in user inputs.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability lies in the importance of proper input sanitization across web applications. It highlights a common failure in security practices, where features that allow user-generated content are not adequately protected. Security teams should learn from this incident to enhance their security posture and prevent similar vulnerabilities.
Organizations can strengthen their defenses through a robust penetration testing program to identify and address vulnerabilities before they can be exploited.
For further reading on improving application security, refer to our vulnerability management program guide, which provides insights into establishing a proactive security strategy.
Additionally, understanding the methodologies behind penetration testing can further enhance how organizations address vulnerabilities effectively.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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