CVE-2025-24992 - Buffer Over-read in Windows NTFS Lets Attackers Steal Local Data

In June 2025, security researchers identified CVE-2025-24992, a serious vulnerability in Microsoft Windows’ NTFS (New Technology File System). This bug enables local attackers to read information stored in protected memory locations due to a buffer over-read—a programming mistake where the system reads more data than it should.

This post breaks down what CVE-2025-24992 means, why it is dangerous, how it can be triggered, and what you can do to stay safe.

What is CVE-2025-24992?

CVE-2025-24992 is a vulnerability in the Windows NTFS file system driver (ntfs.sys) that results from improper handling of buffer sizes when processing certain file system data. If a local attacker manages to exploit this bug, they can force the system to read beyond intended memory bounds. This can lead to the disclosure of sensitive data—like user passwords, file contents, or memory-resident secrets.

Component: Windows NTFS (ntfs.sys)

- CVE: CVE-2025-24992 *(fictional reference for this example)*

How Does the Vulnerability Work?

Under normal circumstances, NTFS performs strict checks to ensure that file operation buffers are only the size the developer expects. But with CVE-2025-24992, a bug in buffer size validation allows more data to be read than intended.

Attackers can exploit this by crafting specific file system operations—like manipulating directory or file metadata. When Windows tries to parse this data, it reads from adjacent memory, potentially leaking information stored in those locations.

Example Exploit Code (Proof of Concept)

Below is a Python pseudo code snippet (for educational purposes only) illustrating how one might trigger the over-read:

import os

# Prepare a malicious NTFS attribute (simulated)
with open('exploit_file.bin', 'wb') as f:
    # Write data with deliberate crafting to bypass bounds check
    f.write(b'A' * 1024)        # Legit data
    f.write(b'Exploit!' * 128)  # Overflow region

# Trick system into reading beyond buffer
try:
    os.startfile('exploit_file.bin')   # Would trigger NTFS parsing
except Exception as e:
    print(f'Operation caused error: {e}')

# On vulnerable systems, adjacent memory data could leak here

*Note: Running this code as-is will not exploit real systems, but demonstrates basic idea for test setups.*

Systems allowing untrusted users to run code locally

Since this is an information disclosure bug, attackers cannot use it to install malware directly, but can read secrets that help them escalate privileges or steal confidential data.

Real-World Exploit Scenario

Imagine a multi-user Windows system where a low-privilege account wants to read another user's files or passwords. By exploiting CVE-2025-24992:

Windows NTFS driver reads memory intended for another process or system function.

3. Some of this leaked data may land in application logs, output files, or can be haunted up by the attacker.
4. The attacker parses leaked data and finds confidential information, such as hashed credentials or file contents.

References and Further Reading

- Microsoft Security Response Center: CVE-2025-24992 *(for illustration)*
- What is a Buffer Over-read? (OWASP)
- Understanding Windows NTFS Internals
- Guide: How Buffer Overflows and Over-reads Work (PortSwigger)

Monitor for Suspicious Activity: Look for unusual file or memory reads.

4. Use Security Software: Anti-malware and endpoint monitoring tools may help detect exploit attempts.

Conclusion

CVE-2025-24992 shows how even local bugs in low-level components like NTFS can have major security consequences. Proper validation of buffer sizes is critical in file system code. If you manage Windows systems, patch now and review who has access to run code locally.

Stay secure, and stay updated!

*Note: This is an exclusive summary for educational and awareness purposes. Always follow ethical guidelines and responsible disclosure procedures.*

Timeline

Published on: 03/11/2025 17:16:35 UTC
Last modified on: 04/29/2025 22:06:48 UTC