Windows 10/11 Vulnerability Exposes NTLM Hashes via Spoofing Attack (CVE-2024-21302)

Windows 10/11 NTLM Hash Disclosure Vulnerability Enables Spoofing Attacks

Security researchers have disclosed a critical vulnerability in Windows 10 and 11 that allows attackers to expose NTLM hashes through a spoofing attack. The flaw, tracked as CVE-2024-21302, was published on Exploit Database and highlights a significant risk for enterprises relying on Windows authentication mechanisms.

Technical Details

The vulnerability exploits weaknesses in the NTLM (NT LAN Manager) authentication protocol, a legacy but still widely used method for network authentication in Windows environments. Attackers can leverage this flaw to:

• Spoof legitimate services to trick users into authenticating to a malicious server.
• Capture NTLM hashes in transit, which can then be cracked offline or used in pass-the-hash attacks.
• Bypass security controls that rely on NTLM for authentication, including some Single Sign-On (SSO) implementations.

The exploit (ID: 52478) does not require elevated privileges, making it accessible to low-level attackers. While Microsoft has not released a detailed advisory, the vulnerability is believed to stem from improper handling of NTLM challenge-response mechanisms.

Impact Analysis

The disclosure of NTLM hashes poses severe risks, including:

• Credential Theft: Attackers can crack NTLM hashes to obtain plaintext passwords, especially if weak or reused credentials are in use.
• Lateral Movement: Compromised hashes can be used in pass-the-hash attacks to move laterally within a network.
• Privilege Escalation: In environments where NTLM is used for privileged access, attackers could escalate their permissions.
• Enterprise Exposure: Organizations using legacy systems, hybrid environments, or third-party integrations that rely on NTLM are particularly vulnerable.

Recommendations for Security Teams

To mitigate the risks associated with CVE-2024-21302, security professionals should:

1. Apply Microsoft Patches: Monitor for and deploy the latest security updates from Microsoft addressing this vulnerability.
2. Disable NTLM Where Possible: Transition to Kerberos or modern authentication protocols (e.g., OAuth 2.0, SAML) to reduce reliance on NTLM.
3. Enforce SMB Signing: Require SMB signing to prevent relay attacks that exploit NTLM.
4. Implement Network Segmentation: Limit lateral movement by segmenting networks and restricting NTLM traffic.
5. Monitor for Suspicious Activity: Use SIEM tools to detect unusual NTLM authentication attempts or hash captures.
6. Educate Users: Train employees to recognize phishing and spoofing attempts that could trigger NTLM authentication.

Next Steps

Given the prevalence of NTLM in enterprise environments, organizations should prioritize patching and protocol hardening. Security teams are advised to review their authentication logs for signs of exploitation and assess their exposure to NTLM-based attacks.

For more details, refer to the original exploit disclosure on Exploit Database.