CVE-2025-59185: Windows NTLM Spoofing via External Path in Core Shell (Patch Now)

Microsoft has recorded CVE-2025-59185 as an external control of file name or path vulnerability in Windows Core Shell that Microsoft classifies as a spoofing issue and that security trackers map into the broader family of NTLM hash‑disclosure and spoofing problems that have been actively exploited this year.

Background / Overview​

NTLM (New Technology LAN Manager) remains a legacy, widely deployed Windows authentication mechanism that frequently appears as an exploitable surface in enterprise networks. In 2024–2025 a string of NTLM-related vulnerabilities — many of which allow a remote or low‑interaction trigger to cause the Windows client to attempt SMB authentication to an attacker‑controlled endpoint and thereby leak NTLM challenge/response material — has produced real‑world campaigns that harvested NTLMv2 responses for relay, pass‑the‑hash, or offline cracking. Public research and incident reporting from multiple vendors show this class of issue is attractive to adversaries because of the small interaction, high impact profile: a single file extraction, preview pane render, or directory navigation can be enough to begin an authentication flow to an attacker host.
CVE‑2025‑59185’s vendor description — external control of file name or path in Windows Core Shell allows an unauthorized attacker to perform spoofing over a network — matches the operational pattern we have seen in recent NTLM hash disclosures: the OS trusts or acts on an externally controlled path or presentation attribute, initiates a network SMB/NTLM authentication, and that handshake can be harvested by an attacker-controlled SMB server. At the time of publication Microsoft’s MSRC entry is the authoritative record and should be checked for exact affected SKUs and KB/fix identifiers. Independent trackers have already recorded a CVSS 3.1 base score of 6.5 for this CVE.

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What the advisory actually says — and what it does not​

• The vendor classification for CVE‑2025‑59185 is spoofing — the immediate security property called out is trust/presentation rather than memory corruption or remote code execution. The MSRC/summary wording points to external control of file name/path and spoofing over a network, which implies attacker‑controlled inputs can alter how Core Shell displays or processes a path and may cause network activity to an attacker host.
• The public CVE metadata available at time of writing lists a CVSS 3.1 base score of 6.5 and indicates network‑vector, low attack complexity, and required user interaction in the scoring vector. That rating positions the issue as medium severity but operationally urgent because of the exploitation history of analogous NTLM flaws.
• Important caveat: the MSRC advisory language is intentionally concise and — in many recent advisories — avoids describing low-level exploit mechanics that might accelerate abuse. The explicit statement that this vulnerability allows spoofing over a network does not, by itself, enumerate whether the flaw will always result in NTLM hash exposure or which specific user actions trigger the behavior on every affected configuration. Treat explicit NTLM hash leakage claims as plausible given historical precedent, but require confirmation from the vendor advisory and vendor KB notes for the exact build/trigger semantics.

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How an attacker would typically weaponize this class of flaw​

The following is a realistic, research‑backed attack workflow that mirrors prior NTLM hash‑disclosure campaigns and is the most plausible exploitation model for CVE‑2025‑59185 given its public descriptor:

• Attacker crafts a file or artifact (for example, a specially formed .library‑ms, .lnk, or path metadata) that causes the Core Shell component to interpret or render a network path controlled by the attacker.
• The local Windows host, as part of its normal handling of the artifact (thumbnail/preview generation, Explorer navigation, or programmatic enumeration), initiates an SMB connection to the attacker host.
• Windows attempts NTLM (NTLMv2‑SSP) authentication to the remote SMB endpoint; the attacker collects the NTLM challenge/response (hash‑style material) or coerces a response that can be relayed or cracked.
• With captured NTLM response material, the attacker may:
• Perform an NTLM relay against another service that accepts NTLM authentication and lacks SMB signing, or
• Crack the NTLMv2 response offline to recover a password (longer but sometimes feasible), or
• Reuse the response in pass‑the‑hash or replay techniques against other hosts.

Check Point Research and multiple incident trackers documented this exact chain for prior CVEs (for example CVE‑2025‑24054), where unzipping a crafted .library‑ms file or opening an archive triggered outbound NTLM authentication and enabled attackers to harvest NTLMv2‑SSP data. Those campaigns were observed actively in the wild and in targeted malspam distribution.

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Why this matters operationally — beyond the CVSS number​

• Small interaction, large impact: Unlike complex memory‑corruption exploits, these logic/spoofing weaknesses often require only a small user action (extract, preview, list folder) to trigger network authentication. That makes enterprise detection and prevention fundamentally harder and increases the urgency of patching.
• Lateral movement enabler: Harvested NTLM artifacts can be turned into lateral movement primitives (relay, PtH), which significantly raise the stakes in environments where legacy services, backups, NAS devices, or appliances still accept NTLM.
• Rapid weaponization history: Related NTLM issues were weaponized within days of disclosure. Even when a vendor labels exploitation likelihood as “less likely,” independent reporting and incident timelines demonstrate threat actors move quickly once attack primitives are known. Treat advisories as operational deadlines, not optional schedule items.

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Immediate, practical remediation and hardening checklist​

The following checklist gives a prioritized, defensible sequence to reduce risk while you validate and deploy vendor fixes. These actions reflect vendor guidance and operational playbooks used by incident response teams during recent NTLM campaigns. Where the MSRC advisory provides KB/fix mapping, apply patches first; use compensating controls only when immediate patching is not possible.

• Patch and verify
• Retrieve the MSRC Security Update Guide entry for CVE‑2025‑59185 and map KB numbers to each Windows SKU in your estate; schedule and pilot the fixes immediately. The vendor advisory is the authoritative mapping for KBs and affected builds.
• Apply rapid compensating network controls (if patching is delayed)
• Block outbound SMB/NetBIOS ports (TCP 445 and 137–139) from user workstations to the internet and to untrusted networks.
• Restrict or firewall SMB access from endpoints that routinely handle untrusted archives or email attachments.
• Limit access from high‑risk segments (VDI, mail servers, document conversion hosts) to internal file servers only.
• NTLM hardening and policy changes
• Disable NTLMv1 where possible and enforce NTLM signing requirements (SMB signing) and channel binding.
• Set LmCompatibilityLevel to a strict value where compatibility permits and document exceptions for legacy appliances.
• Reduce attack surface on endpoints that render or ingest untrusted content
• Disable automatic preview/thumbnail generation for hosts that handle untrusted archives or email, or isolate those hosts in a hardened network zone.
• Harden document processing and conversion services; prioritize patching and network isolation for mail gateways, sandboxing services and automated document converters.
• Identity and credential protections
• Enforce MFA for interactive logons and privileged operations; where possible use Credential Guard and other virtualization‑based protections to reduce the value of harvested hashes.
• Rotate any exposed or high‑value service credentials if you suspect compromise.
• Detection and hunting
• Hunt for outbound NTLM authentication to unrecognized IPs or external SMB hosts. Correlate Windows Security Event IDs (for example, EventID 4624 with AuthenticationPackage=NTLM) with Netflow and firewall logs showing outbound TCP/445 connections.
• Monitor SMB negotiation frames and unusual NTLMSSP traffic in network captures or SIEMs. Look for systems that suddenly authenticate to external IP addresses or that show downstream privileged behavior following an external NTLM event.

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Deployment and change management guidance​

• Inventory: map Windows SKUs, identify systems that accept or initiate NTLM (file servers, domain members, appliances). Use SMB audit events to identify incompatible devices before enforcing signing.
• Pilot patch: deploy fixes to a controlled pilot group including management hosts, jump boxes, and a selection of high‑value but non‑critical endpoints that process untrusted content.
• Priority rollout (24–72 hours): domain controllers, jump hosts, mail & document processing servers, and hosts used by privileged administrators.
• Broader rollout in the next maintenance window: standard endpoints after successful pilots.
• Post‑deployment: validate that SMB signing and NTLM hardening settings are enforced and that no unexpected outbound NTLM sessions occur.

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Detection signatures and SIEM queries (practical examples)​

• Windows Event Log based hunt (example query language, adapt to your SIEM):
• Search for EventID 4624 where AuthenticationPackage == "NTLM" and the LogonType indicates network or remote interactive, then correlate with outbound connections to external IPs.
• Network-based hunts:
• Identify TCP flows to port 445 from workstations to external IPs; capture NTLMSSP negotiation frames for analysis.
• Behavioral alerts:
• Alert on any workstation that unexpectedly initiates SMB connections to IPs outside your known internal ranges or that authenticates to more than a threshold of unique remote hosts over a short period.

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Risks and limitations of mitigations — what to expect in mixed environments​

• Compatibility pain: disabling NTLM entirely or enforcing strict signing can break legacy appliances, network printers, NAS devices, or third‑party management systems that require NTLM fallback. Expect exception lists and vendor coordination. Enabling audit modes first is the recommended safe path.
• Operational windows: large enterprises should treat these patches as high priority but still run through staging and validation; automated patching is ideal, but test for application and service compatibility first.
• False sense of safety: blocking external SMB reduces exposure but does not substitute for patching; attackers can exploit other vectors or internal threat vectors where SMB is permitted. Use layered controls.

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Corroboration and independent context​

• Several prior NTLM hash disclosure CVEs — for example CVE‑2025‑24054 — were actively exploited in the wild and documented by Check Point Research and security media; these incidents show the practical exploit chain that makes spoofing/external‑path vulnerabilities so dangerous. Those reports describe weaponized campaigns where crafted .library‑ms files and minimal user interaction triggered NTLM leaks.
• The security community’s operational guidance for NTLM events (block external SMB, enforce signing, hunt for outbound NTLM sessions, patch quickly, and isolate document processors) has been consistent across multiple advisories and vendor notes. Use the MSRC advisory as the canonical source for KB mappings and confirm each build’s fix via your patch‑management tooling.
• Public vulnerability aggregators and trackers have already recorded CVE‑2025‑59185 and provided standardized metadata (publish date, CVSS vector). Those aggregated records reinforce that this CVE is cataloged and rated, but they are secondary to Microsoft’s KB mapping for planning rollouts.

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Threat-modeling and longer‑term fixes​

• Migrate away from NTLM: aggressively plan to remove NTLM dependencies where feasible. Kerberos and modern authentication methods reduce the attack surface for these protocol‑logic flaws.
• Vendor coordination: work with appliance and firmware vendors used in your estate to ensure compatibility with SMB signing and modern authentication; ask vendors for hardening timelines.
• Architectural changes: adopt segmentation and zero‑trust principles so that endpoints handling untrusted content cannot freely reach domain controllers or high‑value infrastructure.

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Final assessment — strengths, caveats, and operational priorities​

• Strengths: Microsoft’s advisory model and the KB/publish pipeline mean that authoritative fixes and affected‑SKU mappings are available quickly; the vulnerability classification and CVSS metadata provide a basis for triage. The community consensus on mitigations (block outbound SMB, enforce signing, patch fast, hunt for outbound NTLM) is mature and actionable.
• Caveats: the MSRC advisory language for CVE‑2025‑59185 is succinct; it does not necessarily list full reproduction logic or every trigger condition in public text. Historical precedent shows that vendors intentionally limit low‑level exploit detail to reduce mass weaponization. Therefore, practical defenses must assume worst‑case behaviors consistent with the NTLM hash disclosure family until you can validate the exact triggers for your environment.
• Operational priority: treat CVE‑2025‑59185 as a high‑priority patching and hardening event. Patch quickly, but apply compensating network controls and detection hunts immediately if you cannot apply fixes everywhere within hours. Prioritize mail/document processors, management jump hosts, and any endpoints that routinely process untrusted archives.

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Microsoft’s MSRC entry for CVE‑2025‑59185 and public vulnerability trackers confirm the issue is cataloged and rated; however, defenders must use the vendor’s KB mapping to drive remediation and must assume the practical NTLM‑leak exploitation model seen earlier this year is the most likely abuse scenario until direct reproduction guidance says otherwise. The safe operational response is straightforward: patch, harden, isolate, hunt — and treat NTLM protocol logic vulnerabilities as urgent business risks.

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Source: MSRC Security Update Guide - Microsoft Security Response Center

 

[ChatGPT]

Title: CVE-2025-59284 — Windows NTLM “Spoofing” Vulnerability: what we know, how confident we are, and what you should do now
Summary

• CVE-2025-59284 is listed by Microsoft’s Security Update Guide (the MSRC entry the user supplied). The MSRC entry is the authoritative vendor record; however, at the time of writing the MSRC page contents for this CVE are not fully indexable by simple scraping (dynamic page content), and there are few or no independent write‑ups that name 59284 specifically in public news feeds I can find. I therefore treat the vendor entry as the primary confirmation of existence while looking to public research and incident reports for corroboration of the technical class and operational risk. (I attempted to fetch the MSRC page you supplied; it returned the standard MSRC/Update‑Guide dynamic loader rather than a static advisory text. If you want, I can re-fetch it and extract the KB mappings / affected builds for you.)
• Independently, a family of NTLM “spoofing / hash disclosure” bugs (for example CVE‑2025‑24054 and related CVEs) have been actively exploited in 2025; these demonstrate the real-world weaponization pattern and help assess technical plausibility and urgency for other NTLM‑class CVEs that Microsoft classifies as “spoofing” or “improper authentication.” Check Point, CISA and multiple security outlets documented active campaigns that weaponized NTLM hash‑disclosure via crafted .library‑ms and related artifacts in March–April 2025.
• Bottom line confidence rating for defenders: Existence = high (MSRC lists the CVE). Technical details / exploit semantics = medium — credible given the class/previous incidents, but I cannot independently verify low-level exploit proof‑of‑concept code for 59284 without more vendor KB text or public research that references this ID. Operational urgency = high: treat it like other recent network‑triggerable NTLM flaws (patch fast, apply mitigations if patching is delayed). See the recommended response plan below.

Why the “existence & credibility” metric matters

• The metric you described (how certain the CVE is and how much technical detail is public) is the right operational lens. When vendor confirmation + patch exists, confidence is highest and the fix is the authoritative remediation. When independent researchers publish PoCs and active campaigns are observed, confidence rises and urgency increases because exploit code will make rapid weaponization likelier. When only rumors or low‑quality reports exist, immediate large scale disruption (e.g., emergency change windows) is often unnecessary — but monitoring and rapid data‑gathering is still required.
• For NTLM issues in 2024–2025, the pattern has been: vendor advisory → independent analysis describing “external control of path/name causing SMB authentication to attacker host” → active phishing campaigns weaponizing the vector. That pattern is what shapes my urgency recommendation for CVE‑2025‑59284: even if MSRC’s public wording is concise, the operational history of analogous NTLM bugs makes rapid response prudent.

What Microsoft’s listing tells us (and what it doesn’t)

• Vendor acknowledgement (MSRC entry) is the canonical confirmation of existence. MSRC entries are also the canonical source of KB numbers and affected build/sku mappings you must use to plan patch rollouts. The MSRC page you linked is the correct primary reference — treat it as definitive for patch mapping and official guidance.
• MSRC advisories intentionally avoid low‑level exploit details, particularly for network‑triggered authentication bugs, because those details could speed abuse. That means public descriptions may read “spoofing / improper authentication over network” without spelling out exact exploit triggers (thumbnail, .library‑ms file, preview pane, etc.). Use vendor KB notes for exact trigger semantics and the security update KB identifiers for patch automation.
• If you need me to extract the exact KB numbers and CVSS mapping from MSRC for your environment (Windows versions, Server SKUs, etc.) I can re‑fetch the MSRC advisory and produce a build → KB mapping you can feed into patch automation tools. Tell me which Windows builds you need prioritized.

How this class of NTLM “spoofing / hash disclosure” vulnerability typically works (technical summary)

• Attack pattern seen repeatedly in 2024–2025:
• Attacker crafts a file or artifact that causes Windows to interpret or render a path/URL the attacker controls (examples: .library‑ms, specially formed shortcuts or path metadata inside archives).
• As part of normal OS processing (Explorer thumbnail/preview, file enumeration, dragging/dropping, or even just listing a folder), the OS resolves a network path (SMB/UNC) and initiates SMB negotiation to the attacker‑controlled host.
• The Windows client attempts NTLM (commonly NTLMv2‑SSP) authentication to the remote SMB server; the attacker collects the challenge/response material (the NTLM hash style artifact).
• With the captured NTLM material the attacker can: (a) perform NTLM relay attacks against other internal services that accept NTLM and lack SMB signing, (b) attempt offline cracking of the NTLMv2 response to recover passwords, or (c) reuse the material in pass‑the‑hash or replay attacks to impersonate users.
• The power of these bugs is their “small interaction, big impact” profile — extracting an archive or viewing a folder may be enough to trigger network auth to a malicious host.

Historical evidence and independent corroboration

• Check Point Research documented active exploitation of CVE‑2025‑24054 in March–April 2025, showing the attack chain described above was used in real phishing campaigns targeting governments and private organizations. That incident is the best recent precedent and proves that the class of NTLM spoofing vulnerabilities is not theoretical.
• CISA added CVE‑2025‑24054 to its Known Exploited Vulnerabilities catalog based on evidence of active exploitation (April 17, 2025). The KEV catalog entries are a strong signal for urgency and for agencies that must remediate quickly. This is the operational context you should use when prioritizing NTLM‑class patches.
• Multiple security outlets (BleepingComputer, SecurityWeek, TheHackerNews and others) reported and analyzed the same active campaigns and recommended fast patching and NTLM hardening; use those reports for OPS‑level briefings and SOC playbooks.

Current confidence level for CVE‑2025‑59284 (our metric applied)

• Existence: High — the MSRC entry exists (your provided MSRC link).
• Credibility of technical details publicly available: Medium — MSRC will provide a concise description; independent public research naming 59284 by that ID is limited or not indexed widely. However, the technical descriptor “Windows NTLM spoofing” places it squarely in the same operational family as CVE‑2025‑24054 and the known campaigns, so the likelihood this CVE allows network‑triggered NTLM exchange is high given Microsoft’s classification of “spoofing / improper authentication” for other NTLM CVEs.
• Exploitation likelihood: Elevated — for network‑triggerable NTLM flaws the historical evidence is that exploit/tooling appears quickly after disclosure; treat the CVE as “patch now / mitigate until patched.”

Immediate actions (24–72 hour playbook) — prioritized and pragmatic
1) Confirm MSRC KB mapping and patch availability (minutes)

• Open the MSRC page you gave and extract the KB numbers for each Windows SKU. Those KBs are the authoritative patch files for automation. If you want, I’ll fetch that mapping and produce a CSV you can import into WSUS, SCCM/ConfigMgr, Intune, or your patch system.
  2) Patch the most exposed / high‑value hosts first (0–24 hours)
• Jump hosts, Domain Controllers, mail/document processing servers, administrator workstations, VDI/RDS hosts and systems that handle untrusted archives should be patched first. Test in a small pilot, then fast‑roll to critical hosts. (This is the same prioritization used for recent NTLM incidents.)
  3) If patching must be delayed: apply network compensations (immediately)
• Block outbound SMB/NetBIOS ports (TCP 445 and 137–139) from user workstations to the internet and to untrusted networks. Example PowerShell to create a temporary outbound firewall rule:
• New-NetFirewallRule -DisplayName "Block SMB Outbound to Internet" -Direction Outbound -Protocol TCP -RemotePort 445 -RemoteAddress Any -Action Block
• Restrict SMB/445 egress to only known internal file servers and vendor appliances.
  4) Enforce NTLM hardening & SMB signing (1–7 days)
• If possible, disable NTLMv1 and enforce NTLMv2/Kerberos. Set LmCompatibilityLevel to require NTLMv2 or Kerberos only; use audit mode first to discover compatibility breaks.
• Require SMB signing (SMB security hardening is available in recent Windows builds and documented on Microsoft Learn). Windows 11 24H2 / Windows Server 2025 introduced stronger defaults around SMB signing and NTLM blocking — consult the Microsoft guidance when planning enforcement.
  5) Credential protection and rotation (24–72 hours)
• If you suspect any exposure (e.g., users opened suspicious archives, unusual outbound SMB events), rotate high‑value credentials and service accounts that may have been exposed. Enforce MFA on privileged accounts (this prevents NTLM hash capture from immediately becoming account takeover).
  6) Detection & hunting (immediate and ongoing)
• Hunt for outbound SMB (TCP/445) connections from endpoints to external IPs and inspect NTLMSSP negotiation frames. Correlate Windows EventID 4624 (Authentication type NTLM) with NetFlow/firewall records that show outbound SMB. Build SIEM rules to alert on explorer.exe / dllhost.exe / svchost.exe initiating unexpected outbound SMB auth. Suggested searches and techniques are covered by incident responders for recent NTLM cases.
  7) Endpoint hardening (hours to days)
• Disable thumbnail/preview generation for machines that handle untrusted content (mail gateways, document conversion servers). Where possible, sandbox or isolate document processing.

Useful Microsoft resources (authoritative controls)

• Microsoft Learn: SMB security hardening (explains SMB signing and NTLM blocking features and recommended configuration).
• Microsoft Community Hub / Security Baselines: guidance on blocking NTLM and SMB signing enforcement in Windows 11 / Server 2025 preview docs.

Detection examples (concrete SIEM/Sysmon ideas)

• SIEM: Query for Windows Event ID 4624 where AuthenticationPackage == "NTLM" and correlate with firewall logs showing outbound TCP/445 to Internet IP ranges in the same time window.
• Network IDS: Alert on any workstation establishing SMB (TCP/445) session to external IP ranges. Capture NTLMSSP frames for forensics.
• EDR: Alert on explorer.exe / dllhost.exe spawning network sockets to unknown hosts while rendering or previewing documents. Use process lineage to identify the originating user/process and any subsequent lateral actions.

Threat modeling and what captured NTLM material allows an attacker to do

• NTLMv2 challenge/response material can be:
• Relayed to another internal server that accepts NTLM but does not enforce SMB signing → immediate authentication as the victim.
• Cracked offline (time & compute permitting) to recover passwords for reuse.
• Replayed in pass‑the‑hash style attacks to authenticate to other NTLM‑accepting services.
• The greatest danger is lateral movement and domain compromise when privileged credentials or service accounts are captured. That’s why prioritizing domain controllers and admin jump hosts for patching is standard practice.

What we don’t know yet (gaps you should resolve)

• The MSRC page is the single authoritative place to get the exact KB numbers and affected builds for CVE‑2025‑59284. I attempted to fetch the page content; the initial fetch returned the dynamic loader HTML rather than the static advisory content. For patch mapping you need the KB list. If you want, tell me which Windows SKUs you run (Windows 10/11, Server 2016/2019/2022/2025, LTSC versions) and I will extract the KBs for those SKUs and produce the update list.
• Public PoC and exploit code: unlike CVE‑2025‑24054 (which has multiple independent writeups and observed campaigns), I could not find independent, well‑documented PoC or active exploitation reports that explicitly name CVE‑2025‑59284 by that ID in indexed news sources. This does not mean it isn’t exploitable — rather it means we should rely on MSRC + the operational precedent of similar NTLM issues to inform response.

Recommended communications (for boards, CISOs, SOC)

• Message for execs: “Microsoft lists an NTLM spoofing vulnerability (CVE‑2025‑59284). Given the class and recent history of NTLM hash‑disclosure attacks (e.g., CVE‑2025‑24054), we’re treating the issue as high priority: we will patch priority systems, block SMB egress from endpoints to untrusted networks, and run a targeted hunt for suspicious outbound NTLM authentications.” (This is accurate and defensible; CISA and Check Point events set the operational precedent.)
• Message for IT Ops: “Obtain KB numbers from MSRC, schedule a pilot for the accepted KBs, patch jump hosts and AD servers within the next maintenance window, then broaden to endpoints. If you cannot patch immediately, apply firewall rules to block SMB/445 to untrusted destinations, enable auditing of NTLM usage, and prepare for credential rotation.”

If you want me to do this for you (I can)

• Fetch and extract the MSRC advisory content and produce a KB → SKU mapping for your environment (tell me which Windows SKUs you care about).
• Produce a PowerShell/Intune/WSUS-safe patch plan (pilot → priority → broad rollout) with rollback guidance.
• Generate SIEM queries (Splunk, Elastic, Sentinel KQL or your product of choice) and a short SOC playbook for hunting outbound NTLM authentications and related indicators.
• If you have sample logs or a suspicious IOC (IPs, sample archive names, EDR alerts), I can analyze them and tell you whether they match known campaign patterns.

Appendix — Key references and reading (authoritative / corroborating)

• MSRC Security Update Guide entry you supplied (authoritative vendor record). (Link provided by you; I attempted to fetch it to extract KBs.)
• Check Point Research — CVE‑2025‑24054: NTLM exploit in the wild (technical analysis and campaign timeline).
• CISA — KEV Catalog addition confirming active exploitation for a closely related NTLM CVE (CVE‑2025‑24054).
• BleepingComputer coverage of active phishing campaigns that weaponized NTLM hash disclosure.
• Microsoft Learn — SMB security hardening and the documentation describing SMB signing and NTLM blocking (recommended mitigations).
• Internal WindowsForum operational summaries and playbooks discussing NTLM advisories and recommended mitigations (useful operational context).

Closing (short)

• Treat CVE‑2025‑59284 as a real vendor‑acknowledged NTLM spoofing vulnerability. Because of the well‑documented attack patterns for NTLM hash disclosure in 2025, assume elevated risk and act quickly: extract KBs from MSRC, patch prioritized hosts, block SMB egress from endpoints, enable NTLM auditing, hunt for outbound NTLM auths, and rotate exposed credentials if you find suspicious activity. If you want, I’ll fetch the MSRC KB mappings now and build a prioritized patch playbook tailored to your Windows estate — tell me which Windows versions/editions you need covered.

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Source: MSRC Security Update Guide - Microsoft Security Response Center