The U.S. Cybersecurity and Infrastructure Safety Company (CISA) on Thursday added a medium-severity safety flaw impacting Microsoft Home windows to its Identified Exploited Vulnerabilities (KEV) catalog, following experiences of lively exploitation within the wild.
The vulnerability, assigned the CVE identifier CVE-2025-24054 (CVSS rating: 6.5), is a Home windows New Expertise LAN Supervisor (NTLM) hash disclosure spoofing bug that was patched by Microsoft final month as a part of its Patch Tuesday updates.
NTLM is a legacy authentication protocol that Microsoft formally deprecated final yr in favor of Kerberos. In recent times, risk actors have discovered varied strategies to take advantage of the know-how, resembling pass-the-hash and relay assaults, to extract NTLM hashes for follow-on assaults.
“Microsoft Home windows NTLM incorporates an exterior management of file identify or path vulnerability that permits an unauthorized attacker to carry out spoofing over a community,” CISA stated.
In a bulletin printed in March, Microsoft stated the vulnerability might be triggered by minimal interplay with a specifically crafted .library-ms file, resembling “deciding on (single-click), inspecting (right-click), or performing an motion aside from opening or executing the file.”
The tech big additionally credited Rintaro Koike with NTT Safety Holdings, 0x6rss, and j00sean for locating and reporting the flaw.
Whereas Microsoft has given CVE-2025-24054 an exploitability evaluation of “Exploitation Much less Seemingly,” the safety flaw has since come below lively exploitation since March 19, per Test Level, thereby permitting unhealthy actors to leak NTLM hashes or person passwords and infiltrate programs.
“Round March 20–21, 2025, a marketing campaign focused authorities and personal establishments in Poland and Romania,” the cybersecurity firm stated. “Attackers used malspam to distribute a Dropbox hyperlink containing an archive that exploited a number of identified vulnerabilities, together with CVE-2025-24054, to reap NTLMv2-SSP hashes.”
The flaw is assessed to be a variant of CVE-2024-43451 (CVSS rating: 6.5), which was patched by Microsoft in November 2024 and has additionally been weaponized within the wild in assaults focusing on Ukraine and Colombia by risk actors like UAC-0194 and Blind Eagle.
In accordance with Test Level, the file is distributed by way of ZIP archives, inflicting Home windows Explorer to provoke an SMB authentication request to a distant server and leak the person’s NTLM hash with none person interplay merely upon downloading and extracting the archive’s contents.
That stated, one other phishing marketing campaign noticed as not too long ago as March 25, 2025, has been discovered delivering a file named “Information.doc.library-ms” with none compression. For the reason that first wave of assaults, a minimum of 10 campaigns have been noticed with the tip aim of retrieving NTLM hashes from the focused victims.
“These assaults leveraged malicious .library-ms recordsdata to gather NTLMv2 hashes and escalate the danger of lateral motion and privilege escalation inside compromised networks,” Test Level stated.
“This fast exploitation highlights the essential want for organizations to use patches instantly and be sure that NTLM vulnerabilities are addressed of their environments. The minimal person interplay required for the exploit to set off and the benefit with which attackers can acquire entry to NTLM hashes make it a big risk, particularly when such hashes can be utilized in pass-the-hash assaults.”
Federal Civilian Government Department (FCEB) companies are required to use the mandatory fixes for the shortcoming by Might 8, 2025, to safe their networks in mild of lively exploitation.
