Understanding CVE-2025-24054: How it Targets and Steals NTLM Credentials During File Download
issue that allows the attacker to steal network password hashes via the download of a seemingly innocent file.
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Details about the Attack
The newly listed vulnerability resides in the handling of SMB traffic by Microsoft’s file sharing protocols.
More specifically, an attacker can trick victims into accessing a malicious SMB server and steal the victims’ NTLM hash credentials the moment a file download is initiated.
This attack plays out similarly to past incidents involving NTLM leaking, such as the SMBGhost flaw (CVE-2020-0796).
However, CVE-2025-24054 takes advantage of a different attack vector that so far remained unexploited.
Real-World Implications
By disseminating seemingly benign files carrying the exploit—as email attachments, for example—attackers could gain unauthorized access to architecture supporting critical information infrastructures.
Such breaches have devastating consequences.
Any disruption to these systems poses a risk to national security, public health and safety, economic vitality, and way of life.
Best Practices for Mitigation
Despite the active exploitation, there are preventive actions that security professionals can undertake:
- Block outbound SMB traffic at your network boundary to prevent credentials sent in plaintext from leaving the intranet, as recommended in Microsoft’s SMB Security Best Practices.
- Consider migrating to Kerberos authentication instead of NTLM whenever possible, as it is more secure.
- Enable Network Level Authentication (NLA) to add an extra layer of protection to your systems.
- Apply patches in a timely manner, as soon as they become available.
Users of affected Windows versions should patch immediately.
Follow-Up Reading
If you would like to learn more about this topic, the following sources might be particularly helpful:
- Official CVE-2025-24054 Details
- Microsoft’s Overview of NTLM Security
- CISA’s Known Exploited Vulnerabilities Catalog
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With adversaries constantly evolving in sophistication, staying up-to-date on vulnerabilities and mitigation strategies is crucial for all cybersecurity professionals.
Protecting sensitive data and maintaining the integrity of network systems must always remain the top priority.
