Microsoft's March and April 2025 Patch Tuesday updates have revealed and addressed a troubling development in cybersecurity: the rapid weaponization of a "less likely to be exploited" NTLM hash-leaking vulnerability, CVE-2025-24054, alongside other critical zero-day flaws emerging in both Microsoft Windows and Apple iOS platforms. These incidents not only highlight persistent weaknesses in legacy authentication protocols like NTLM but also underscore the urgency for immediate patch deployment and broader reevaluation of security practices in enterprise and consumer environments.
On March 11, 2025, Microsoft released its routine Patch Tuesday update bundle, which among other fixes included a patch for CVE-2025-24054. This vulnerability affects the way Windows handles NTLM authentication hashes, specifically enabling an attacker to leak a victim’s NTLM (and Net-NTLMv2) hashes over a network with minimal user interaction. Microsoft had rated the risk as "less likely" to be exploited, but cybercriminals acted fast to prove otherwise.
Security researchers at Check Point detailed how attackers weaponized this NTLM vulnerability within just eight days. Malicious actors used a cleverly crafted ZIP archive hosted on Dropbox, named xd.zip, containing booby-trapped files, including a .library-ms file. The simple act of extracting the archive or even just viewing the folder containing the malicious file in Windows Explorer triggered an outbound SMB (Server Message Block) authentication attempt, exposing the victim’s Net-NTLMv2 hash to a remote server under attacker control. Once attackers obtained these hashes, they could perform offline brute-force attacks or relay the hashes to impersonate the victim user, potentially gaining unauthorized access to sensitive systems and data.
By March 25, attackers further refined their tactics by sending the .library-ms files directly in emails, eliminating the need for archive extraction. Microsoft confirmed the exploit could trigger with minimal interaction: even a single or right-click was sufficient. This ease of exploitation combined with the capability to conduct pass-the-hash attacks magnifies the danger. Check Point observed at least ten concurrent campaigns targeting organizations internationally, including government and private sector victims in Poland and Romania, with stolen hashes exfiltrated to a network of SMB servers located in Russia, Bulgaria, the Netherlands, Australia, and Turkey. Intriguingly, the primary exfiltration IP was linked to infrastructure previously flagged with connections to the Russian-linked hacker group APT28 (Fancy Bear), though no direct attribution was confirmed.
Given the minimal user interaction required and the ubiquity of Windows Explorer, this vulnerability exposed a wide range of systems effortlessly. The hash obtained, whether NTLMv2 or Net-NTLMv2-SSP, can be used to surreptitiously gain unauthorized network access through so-called "pass-the-hash" techniques without needing the original password, effectively bypassing many traditional security barriers.
The broader implication is a resounding call for organizations to move beyond just patching to fundamentally reassess their reliance on NTLM. Experts recommend transitioning to more secure modern authentication protocols such as Kerberos, strengthening network segmentation to limit lateral attacker movement, implementing multi-factor authentication (MFA) wherever feasible, and conducting comprehensive monitoring of anomalous authentication behaviors. In the meantime, immediate patch application and heightened user vigilance against suspicious emails or unexpected file handling remain critical defenses.
The first vulnerability was a memory corruption flaw in Apple’s CoreAudio framework, responsible for processing audio streams. Exploiting this defect through a maliciously crafted media file could allow an attacker to achieve arbitrary code execution on the device, potentially leading to full device compromise.
The second targeted the Return Pointer Authentication Code (RPAC) mechanism, an Apple technology designed to protect against pointer manipulation attacks that are often a vector for exploits. The vulnerability allowed attackers with arbitrary read and write access to bypass this security feature. Apple's mitigation entailed removing the vulnerable code path to neutralize this attack vector.
These patches underscore the continuous risks modern OSes face from highly targeted and complex exploit chains. While the scale of attacks differs—Windows focusing on potentially broad exploitation via legacy protocols, and Apple on surgically-targeted zero-days—the commonality is the urgency and sophistication of these threats.
In total, Microsoft's April release addressed various classes of vulnerabilities including remote code execution flaws in Microsoft Office, Windows Hyper-V, and Remote Desktop Services (RDP), along with privilege escalation and information disclosure issues. The wide surface area of attack vectors—from file system drivers to virtualization components and authentication mechanisms—reflects the complex and layered nature of modern cybersecurity challenges.
Alongside, Microsoft's advisory noted other vulnerabilities affecting Lightweight Directory Access Protocol (LDAP), Windows Mark of the Web (MotW) bypass flaws, and credential protection bypasses in Windows Defender Credential Guard.
For organizations and individuals, the message is clear. Patch quickly and comprehensively. Reassess legacy protocol usage and security configurations. Educate users on the evolving threat landscape. And deploy layered defenses that include proactive monitoring and strict access controls. In a world where a single file viewed in Windows Explorer or a crafted media file on a smartphone can topple digital defenses, cybersecurity cannot be static or reactive—it must be vigilant, adaptive, and holistic.
By understanding these threats’ mechanisms and implications, IT professionals can better prepare defenses against both the common and the cutting-edge, safeguarding the integrity of their digital environments in an ever-shifting security terrain.
References for this analysis and technical details can be found in the detailed discussions and advisories documented in WindowsForum.com community threads and Microsoft security bulletins, as well as technical reports from Check Point, Apple, and other cybersecurity firms.
Source: Eight days from patch to exploitation for Microsoft flaw
The NTLM Hash-Leaking Vulnerability: CVE-2025-24054
On March 11, 2025, Microsoft released its routine Patch Tuesday update bundle, which among other fixes included a patch for CVE-2025-24054. This vulnerability affects the way Windows handles NTLM authentication hashes, specifically enabling an attacker to leak a victim’s NTLM (and Net-NTLMv2) hashes over a network with minimal user interaction. Microsoft had rated the risk as "less likely" to be exploited, but cybercriminals acted fast to prove otherwise.Security researchers at Check Point detailed how attackers weaponized this NTLM vulnerability within just eight days. Malicious actors used a cleverly crafted ZIP archive hosted on Dropbox, named xd.zip, containing booby-trapped files, including a .library-ms file. The simple act of extracting the archive or even just viewing the folder containing the malicious file in Windows Explorer triggered an outbound SMB (Server Message Block) authentication attempt, exposing the victim’s Net-NTLMv2 hash to a remote server under attacker control. Once attackers obtained these hashes, they could perform offline brute-force attacks or relay the hashes to impersonate the victim user, potentially gaining unauthorized access to sensitive systems and data.
By March 25, attackers further refined their tactics by sending the .library-ms files directly in emails, eliminating the need for archive extraction. Microsoft confirmed the exploit could trigger with minimal interaction: even a single or right-click was sufficient. This ease of exploitation combined with the capability to conduct pass-the-hash attacks magnifies the danger. Check Point observed at least ten concurrent campaigns targeting organizations internationally, including government and private sector victims in Poland and Romania, with stolen hashes exfiltrated to a network of SMB servers located in Russia, Bulgaria, the Netherlands, Australia, and Turkey. Intriguingly, the primary exfiltration IP was linked to infrastructure previously flagged with connections to the Russian-linked hacker group APT28 (Fancy Bear), though no direct attribution was confirmed.
Why CVE-2025-24054 is Particularly Dangerous
NTLM has long been recognized as a security legacy protocol riddled with weaknesses such as susceptibility to replay and relay attacks. The core issue lies in the authentication mechanism's reliance on hashed credentials transmitted over the network, which can be intercepted and reused by skilled adversaries. CVE-2025-24054 exploits an edge case where an external control over file names or paths in conjunction with Windows Explorer's handling of .library-ms files causes unintended NTLM authentication requests to malicious servers, leaking critical hash data.Given the minimal user interaction required and the ubiquity of Windows Explorer, this vulnerability exposed a wide range of systems effortlessly. The hash obtained, whether NTLMv2 or Net-NTLMv2-SSP, can be used to surreptitiously gain unauthorized network access through so-called "pass-the-hash" techniques without needing the original password, effectively bypassing many traditional security barriers.
The broader implication is a resounding call for organizations to move beyond just patching to fundamentally reassess their reliance on NTLM. Experts recommend transitioning to more secure modern authentication protocols such as Kerberos, strengthening network segmentation to limit lateral attacker movement, implementing multi-factor authentication (MFA) wherever feasible, and conducting comprehensive monitoring of anomalous authentication behaviors. In the meantime, immediate patch application and heightened user vigilance against suspicious emails or unexpected file handling remain critical defenses.
Apple’s Simultaneous Patching of Two Zero-Days in iOS and iPadOS
Amid these Windows security challenges, Apple concurrently addressed two distinct zero-day vulnerabilities in iOS and iPadOS 18.4.1, released the week following Microsoft's March Patch Tuesday. These flaws were actively exploited against targeted individuals in "extremely sophisticated" attacks.The first vulnerability was a memory corruption flaw in Apple’s CoreAudio framework, responsible for processing audio streams. Exploiting this defect through a maliciously crafted media file could allow an attacker to achieve arbitrary code execution on the device, potentially leading to full device compromise.
The second targeted the Return Pointer Authentication Code (RPAC) mechanism, an Apple technology designed to protect against pointer manipulation attacks that are often a vector for exploits. The vulnerability allowed attackers with arbitrary read and write access to bypass this security feature. Apple's mitigation entailed removing the vulnerable code path to neutralize this attack vector.
These patches underscore the continuous risks modern OSes face from highly targeted and complex exploit chains. While the scale of attacks differs—Windows focusing on potentially broad exploitation via legacy protocols, and Apple on surgically-targeted zero-days—the commonality is the urgency and sophistication of these threats.
Broader Security Landscape and Microsoft’s Patch Priority
Microsoft's April 2025 Patch Tuesday further emphasized the continued severity of vulnerabilities across its ecosystem. This update tackled 121 distinct fixes including another high-profile zero-day: CVE-2025-29824, a use-after-free vulnerability in the Windows Common Log File System (CLFS), already exploited by threat actors such as the ransomware group RansomEXX. The exploitation enables privilege escalation to SYSTEM level and is considered critical.In total, Microsoft's April release addressed various classes of vulnerabilities including remote code execution flaws in Microsoft Office, Windows Hyper-V, and Remote Desktop Services (RDP), along with privilege escalation and information disclosure issues. The wide surface area of attack vectors—from file system drivers to virtualization components and authentication mechanisms—reflects the complex and layered nature of modern cybersecurity challenges.
Alongside, Microsoft's advisory noted other vulnerabilities affecting Lightweight Directory Access Protocol (LDAP), Windows Mark of the Web (MotW) bypass flaws, and credential protection bypasses in Windows Defender Credential Guard.
Risk Mitigation: Essential Practices for IT Teams
The rapid exploitation of CVE-2025-24054 and related vulnerabilities delivers several stark lessons:- Immediate Patch Application: Delays in patching expose systems to active and automated attacks. As seen, "less likely" severity ratings provide no guarantee against rapid exploitation.
- Legacy Protocol Reassessment: NTLM’s persistent use poses risks that accumulate over time with emerging vulnerabilities. Transitioning to Kerberos and removing unnecessary NTLM dependencies is advisable.
- User Awareness and Limited Interaction: Even minimal user actions like clicking or right-clicking files can trigger exploits. User education on safe file handling and cautious email practices is vital.
- Network Segmentation and Zero Trust: Making lateral movement harder through segmentation and enforcing zero-trust models helps contain breaches even if credentials are compromised.
- Advanced Monitoring: Close observation of anomalous SMB authentications, LDAP requests, and hash usage patterns can provide early warnings of ongoing attacks.
- Use of Multi-Factor Authentication: MFA remains a critical line of defense when credential hashes are leaked, reducing risk of unauthorized access despite stolen hashes.
Conclusion
The events around CVE-2025-24054 and Apple’s zero-day patches paint a clear picture of the prevailing cybersecurity battleground: attackers are nimble and exploit even newly patched vulnerabilities with alarming speed. Legacy weaknesses, especially in Windows authentication protocols like NTLM, provide persistent attack avenues that sophisticated adversaries readily weaponize.For organizations and individuals, the message is clear. Patch quickly and comprehensively. Reassess legacy protocol usage and security configurations. Educate users on the evolving threat landscape. And deploy layered defenses that include proactive monitoring and strict access controls. In a world where a single file viewed in Windows Explorer or a crafted media file on a smartphone can topple digital defenses, cybersecurity cannot be static or reactive—it must be vigilant, adaptive, and holistic.
By understanding these threats’ mechanisms and implications, IT professionals can better prepare defenses against both the common and the cutting-edge, safeguarding the integrity of their digital environments in an ever-shifting security terrain.
References for this analysis and technical details can be found in the detailed discussions and advisories documented in WindowsForum.com community threads and Microsoft security bulletins, as well as technical reports from Check Point, Apple, and other cybersecurity firms.
Source: Eight days from patch to exploitation for Microsoft flaw
