CISA added a medium-severity Windows vulnerability, CVE-2025-24054, to its Known Exploited Vulnerabilities catalog. The vulnerability is a NTLM hash disclosure spoofing bug, which Microsoft patched in its recent Patch Tuesday updates. NTLM is a legacy authentication protocol now replaced by Kerberos, but threat actors continue to exploit it for pass-the-hash and relay attacks. The vulnerability allows unauthorized attackers to perform spoofing actions over a network, leaking NTLM hashes and user passwords.
Microsoft assigned the flaw a CVSS score of 6.5 and labeled it as “Exploitation Less Likely.” However, active exploitation began shortly after its discovery, with campaigns targeting institutions in Poland and Romania. Cybersecurity firm Check Point linked these attacks to malicious emails that contained links to Dropbox archives. The archive exploited CVE-2025-24054 to harvest NTLMv2-SSP hashes, allowing attackers to infiltrate systems without user interaction.
In addition to the ongoing exploitation of this vulnerability, researchers discovered another campaign delivering a file named “Info.doc.library-ms.” This method bypasses user interaction requirements, making it easier for attackers to leak NTLM hashes. Over 10 campaigns have been identified targeting this flaw, with attackers focusing on lateral movement and privilege escalation within compromised networks. These attacks highlight the ease with which bad actors can exploit this flaw to gain access to sensitive network credentials.
CISA has urged organizations, especially federal agencies, to apply necessary patches immediately to mitigate the risk posed by this vulnerability. Federal Civilian Executive Branch agencies must secure their networks by May 8, 2025, to prevent further exploitation. The minimal user interaction required for this exploit makes it a significant threat, underscoring the urgency of addressing NTLM vulnerabilities in affected environments.
