The Common Vulnerabilities and Exposures (CVE) system has assigned the identifier CVE-2024-26160 to a newly discovered information disclosure vulnerability within the Windows Cloud Files Mini Filter Driver. This post aims to provide a comprehensive analysis of the issue, relevant code snippets, links to original references, and a discussion of potential exploit details.

Overview

The vulnerability in question revolves around the Windows Cloud Files Mini Filter Driver, which is responsible for providing a synchronization mechanism between local files and cloud storage services like Microsoft OneDrive. The issue occurs due to improper handling of certain types of requests, which may lead to unauthorized disclosure of sensitive data stored in the system's memory.

Original References

Microsoft Security Response Center (MSRC) has published a detailed advisory on this vulnerability, which can be accessed through the following link:

- MSRC Advisory CVE-2024-26160

Code Snippet

The problem is rooted in the way the Mini Filter Driver processes specific IOCTL (Input/Output Control) requests. The following code snippet demonstrates the improper handling of IOCTL requests, leading to information disclosure:

NTSTATUS FILTERAPI CloudFilterCallback(
    _In_ PFLT_CALLBACK_DATA Data,
    _In_ PCFLT_RELATED_OBJECTS FltObjects,
    _Flt_CompletionContext_Outptr_ PVOID *CompletionContext)
{
    ...
    switch (IoControlCode)
    {
        ...
        case IOCTL_CLOUD_FILE_QUERY_INFO:
            {
                ...
                // Improper validation of user-supplied buffer size
                if (Data->Iopb->Parameters.DeviceIoControl.OutputBufferLength >= sizeof(CLOUD_FILE_QUERY_INFO))
                {
                    PAGED_CODE();
                    RtlCopyMemory(OutputBuffer,
                                  &queryInfo,
                                  sizeof(CLOUD_FILE_QUERY_INFO));
                }
                ...
            }
            break;
        ...
    }
    ...
}

In the code above, the driver fails to validate the user-supplied buffer size before calling RtlCopyMemory(). This action may lead to the disclosure of other sensitive information stored in the system's memory.

Exploit Details

Although there is no public exploit code available at the time of writing, threat actors may develop an exploit based on the vulnerability's details. The following steps outline a hypothetical approach to exploiting the vulnerability:

An attacker would first need to gain access to the local machine and obtain user-level privileges.

2. Next, they would craft a malicious IOCTL request targeting the Cloud Files Mini Filter Driver with an insufficient buffer size.
3. The attacker would then send the IOCTL request to the driver and capture the disclosed memory contents in the output buffer.

By following these steps, an attacker could potentially retrieve sensitive information such as encryption keys, user credentials, or other critical system data.

Users are advised to apply the latest security updates provided by Microsoft, as per their advisory

- Download Security Update for Windows

Additionally, it is recommended to follow security best practices like keeping software up-to-date, employing strong authentication measures, and monitoring system logs for suspicious activities.

Conclusion

CVE-2024-26160 is a critical information disclosure vulnerability affecting the Windows Cloud Files Mini Filter Driver. Proper understanding of the issue, its potential exploits, and mitigation strategies are crucial in protecting sensitive data and maintaining a secure computing environment. Always be vigilant and stay updated with the latest security information to minimize your risk exposure.

Timeline

Published on: 03/12/2024 17:15:55 UTC
Last modified on: 03/12/2024 17:46:17 UTC