NTLM

Security Advisory

Microsoft October Patch Fixes 175 Vulnerabilities, 6 Zero-Days & Critical Exploits 

Summary:  Microsoft’s October 2025 Patch Tuesday fixes 175 security vulnerabilities in the products Windows, Office, Azure, and .NET and others. It includes patches for 6 – zero-day vulnerabilities where three vulnerabilities have been exploited and three publicly known vulnerabilities.  

Microsoft advises immediate deployment of updates and removal of affected drivers, while assessing legacy fax hardware for compatibility issues introduced by the driver removal in this month update.

The October 2025 security updates address critical and important vulnerabilities across a broad range of Microsoft products and services. 

OEM Microsoft 
Severity Critical 
Date of Announcement 2025-10-14 
No. of Patches 175 
Actively Exploited Yes 
Exploited in Wild Yes 
Advisory Version 1.0 

Overview 

Major fixes address serious remote code execution issues in Office and WSUS, along with privilege escalation vulnerabilities in Windows and Azure. The update also removes the Agere Modem driver, which could affect older fax devices. Users & Administrator are urged to update the patch to immediately to stay protected. 

Here are the CVE addresses for Microsoft & non-Microsoft:  

  • 175 Microsoft CVEs addressed 
  • 21 non-Microsoft CVEs addressed (Republished) 

Breakdown of October 2025 Vulnerabilities 

  • 80 Elevation of Privilege (EoP) 
  • 31 Remote Code Execution (RCE) 
  • 28 Information Disclosure 
  • 11 Denial of Service (DoS) 
  • 11 Security Feature Bypass 
  • 12 Spoofing  
  • 2 Tampering 

Source: Microsoft 

Vulnerability Name CVE ID Product Affected Severity CVSS Score 
Windows Agere Modem Driver Elevation of Privilege Vulnerability CVE-2025-24990 Windows 10, 11, Server 2016-2022 High 7.8 
Windows Remote Access Connection Manager Elevation of Privilege Vulnerability CVE-2025-59230 Windows 10, 11, Server 2016-2022 High 7.8 
Secure Boot Bypass Vulnerability in IGEL OS CVE-2025-47827 IGEL OS Medium 4.6 
Windows Server Update Service (WSUS) Remote Code Execution Vulnerability CVE-2025-59287 Windows Server Critical 9.8 
Microsoft Office Remote Code Execution Vulnerability CVE-2025-59234 Microsoft Office High 7.8 
Microsoft Excel Remote Code Execution Vulnerability CVE-2025-59236 Microsoft Excel (2016-2021) High 8.4 

Technical Summary 

October 2025 Patch Tuesday includes security updates addresses remote code execution, privilege escalation and information disclosure vulnerabilities in core Windows components, Office applications and Azure cloud services.

3 zero-days are actively exploited, including CVE-2025-24990 in the Agere Modem driver, where attackers can abuse the third-party component to gain administrative privileges without needing the modem hardware active, leading to local system compromise.  

Additionally, exposes improper access controls in Windows Remote Access Connection Manager, enabling authorized attackers to escalate to SYSTEM privileges with moderate effort.  

CVE ID System Affected  Vulnerability Details Impact 
CVE-2025-24990 Windows Agere Modem Driver Third-party driver abused for admin privileges; removed in updates, may break fax modem hardware Privilege Escalation 
CVE-2025-59230 Windows Remote Access Connection Manager Improper access control allows local attackers to gain SYSTEM privileges Privilege Escalation 
CVE-2025-47827 IGEL OS < v11 Improper cryptographic signature verification enables Secure Boot bypass via crafted root filesystem Security Feature Bypass 
CVE-2025-59287 Windows Server Update Service Deserialization of untrusted data allows unauthenticated RCE over networks, prime for supply-chain attacks Remote Code Execution 
CVE-2025-59234 Microsoft Office (2016-2021) Use-after-free in Office allows RCE via malicious files, no authentication required Remote Code Execution 
CVE-2025-59236 Microsoft Excel (2016-2021) Use-after-free in Excel enables RCE via malicious files, potentially leading to system control Remote Code Execution 

Source: Microsoft 

In addition to several other publicly exploited Zero-Day & Critical severity issues were addressed 

  • CVE-2025-0033: AMD SEV-SNP Flaw – Race condition in AMD EPYC processors allows hypervisor to tamper with guest memory; needs privileged access. (Critical) 
  • CVE-2025-24052: Windows Agere Modem EoP – Flaw in modem driver enables local admin privilege escalation; driver removed, may affect fax hardware. (High) 
  • CVE-2025-2884: TCG TPM 2.0 Vulnerability – Out-of-bounds read in TPM cause info disclosure or DoS, impacting secure boot. (Medium) 
  • CVE‑2025‑49708: Microsoft Graphics Component EoP – Memory corruption enables network-based privilege escalation.  (Critical) 
  • CVE-2025-59227: Microsoft Office RCE – Use-after-free affecting multiple Office versions. (Critical) 
  • CVE-2016-9535: LibTIFF Heap Buffer Overflow – RCE via malformed TIFF files in image processing. (Critical) 
  • CVE-2025-59291 & CVE-2025-59292: Azure Container Instances/Compute Gallery EoP – External file path control for local privilege escalation. (Critical) 

Key Affected Products and Services 

  • Windows Core and Security Components 

Updates for Windows Kernel, NTFS, BitLocker, NTLM, SMB, WinSock, PrintWorkflowUserSvc and Remote Desktop Services, with several vulnerabilities rated CVSS 7.8 or higher. 

  • Microsoft Office Suite 

Patches for Excel, Word, PowerPoint, Visio, and SharePoint addressing RCE and information disclosure issues, particularly via malicious file execution. 

  • Azure and Cloud Services 

Fixes for Azure Entra ID, Monitor Agent, Connected Machine Agent, PlayFab and Confidential Container Instances. 

  • Virtualization and Hyper-V 

Vulnerabilities in Hyper-V and Virtual Secure Mode, including privilege escalation and DoS risks. 

  • Developer and Management Tools 

Updates for PowerShell, Visual Studio and Configuration Manager addressing local privilege escalation. 

  • Communication & File Services 

Patches for SMB, WSUS, and Connected Devices Platform with critical RCE and lateral movement risks. 

  • Browsers and Web Technologies 

Microsoft Edge (Chromium-based) updates, including republished Chrome CVEs. 

Remediation: 

  • Install the October 2025 security updates immediately to mitigate risks. 

Here are some recommendations below  

  • Use EDR tools to monitor any indicators like Office crashes or logs. 
  • Disable unused services to prevent any remote access or other exploitation. 
  • Apply least privilege access in Office and Azure environments. 
  • Segment networks to reduce any lateral movement. 

Conclusion: 
Critical RCE flaws in Office and WSUS, along with privilege escalation bugs, pose significant risks for ransomware, data theft and lateral movement. Administrator, users & security teams should deploy patches immediately, enhance monitoring and apply mitigations to reduce exposure. 

References: 

Security Advisory

Windows Zero-Day Exploit NTLM Hash Disclosure via Malicious Files

Summary

OEMMicrosoft
SeverityHigh
CVEsNot Yet Assigned
Exploited in WildNo
Patch/Remediation AvailableNo
Advisory Version1.0
Vulnerability Zero-Day

Overview

A newly discovered NTLM vulnerability in Windows, allows attackers to obtain login credentials when a user view a malicious file in Windows Explorer. This issue affects all Windows versions, from Windows 7 and Server 2008 R2 to the most recent Windows 11 v24H2 and Server 2025.

Attackers can exploit this flaw by using shared network folders, USB drives, or previously downloaded malicious files, making credential theft easy and difficult to detect.

Vulnerability NameCVE IDProduct AffectedSeverityFix
             NTLM Hash Disclosure Vulnerability      Not Yet Assigned    Windows OS and Windows Server         High  Unofficial micropatch available via 0patch

Technical Summary

This vulnerability enables attackers to steal NTLM authentication credentials simply by having users view a malicious file in Windows Explorer. Unlike previous NTLM relay attack techniques that required users to execute files, this exploit works just by rendering the malicious file’s metadata in the Windows Explorer preview pane. Attackers can leverage this method in various ways:

  • Hosting a shared network folder containing the malicious file.
  • Distributing infected USB drives that trigger the attack when inserted.
  • Tricking users into downloading the malicious file from a compromised or attacker-controlled website.

Once the credentials are captured, attackers can use NTLM relay attacks to gain unauthorized access to internal systems, escalate privileges, and move laterally across the network.

CVE IDSystem AffectedVulnerability Technical DetailsImpact
  Not Assigned Yet  Windows 7 – Windows 11 v24H2, Server 2008 R2 – Server 2025Attackers can capture NTLM credentials when users view malicious files in Windows Explorer. Exploitation methods include shared folders, USB drives, or downloads.Credential theft, network compromise, and potential lateral movement.  

Recommendations

  • Microsoft Patch Awaited: The vulnerability has been reported to Microsoft, and an official security update is expected in the near future.
  • Unofficial Micropatch Available: Security researchers at 0patch have released an unofficial micropatch that mitigates this issue. The micropatch is available for all affected Windows versions and will remain free until an official fix is provided by Microsoft.

Steps to Apply 0patch Micropatch:

  1. Create a free account on 0patch Central.
  2. Install and register the 0patch Agent on affected systems.
  3. The micropatch is applied automatically without requiring a system reboot.

Security Best Practices

  • Disable NTLM authentication where possible.
  • Implement SMB signing to prevent relay attacks.
  • Restrict access to public-facing servers like Exchange to limit credential relaying risks.
  • Educate users to avoid interacting with unknown or suspicious files in shared folders and USB drives.

Conclusion

Although not classified as critical, this NTLM credential theft vulnerability is extremely harmful due to its ease of exploitation. Attackers can exploit NTLM hashes in relay attacks to compromise internal network resources.

Security researchers confirm that comparable flaws have been actively exploited in real-world assaults. Until an official Microsoft patch is available, organizations should prioritize applying the 0patch micropatch and following NTLM security best practices to reduce potential risks.

References:

Security Advisory

Microsoft Updates Patch Tuesday for Feb 2025; Address 67 Vulnerabilities, Includes 2 Exploited Zero-Days 

Summary

Microsoft’s February 2025 Patch Tuesday addresses multiple security vulnerabilities, including four zero-days, with two actively exploited in the wild. This update covers a total of 67 security flaws, with three classified as critical Remote Code Execution (RCE) vulnerabilities.  

Microsoft  issued a revision for an older zero-day that threatens the latest Windows desktop and server versions.

OEM Microsoft 
Severity Critical 
Date of Announcement 2025-02-11
No. of Vulnerabilities Patched 67 
Actively Exploited Yes 
Exploited in Wild Yes 
Advisory Version 1.0 

Overview 

The affected products include Windows, Microsoft Office, Microsoft Surface, and various network services. Organizations are strongly advised to apply these patches immediately to mitigate security risks and potential cyberattacks. 

  • 63 Microsoft CVEs addressed 
  • 4 non-Microsoft CVEs included 

The highlighted vulnerabilities include 4 zero-day flaws, 2 of which are currently being actively exploited. 

Vulnerability Name CVE ID Product Affected Severity CVSS Score 
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability CVE-2025-21418 Windows High 7.8 
Windows Storage Elevation of Privilege Vulnerability  CVE-2025-21391 Windows High 7.1 
Microsoft Surface Security Feature Bypass Vulnerability CVE-2025-21194 Windows High  7.1 
NTLM Hash Disclosure Spoofing Vulnerability CVE-2025-21377 Windows Medium  6.5 

Technical Summary 

CVE ID System Affected Vulnerability Details Impact 
  CVE-2025-21418  Windows server and Windows 10 & 11  Windows ancillary function driver for winsock elevation of privilege vulnerability enables attackers to escalate privileges to SYSTEM level. Specific exploitation details are not disclosed.    Unauthorized access with SYSTEM privileges.  
  CVE-2025-21391  Windows server and Windows 10 & 11 Windows storage elevation of privilege vulnerability allows attackers to delete targeted files on a system, potentially leading to service unavailability. Does not expose confidential data.    Deletion of critical data, leading to service disruption. 
  CVE-2025-21194    Microsoft Surface    Microsoft surface security feature bypass vulnerability allows attackers to bypass UEFI protections, compromising the secure kernel. Likely related to “PixieFail” vulnerabilities affecting the IPv6 network stack in Tianocore’s EDK II firmware.    Bypass of security features, potentially compromising system integrity. 
 CVE-2025-21377  Windows server and Windows 10 & 11 NTLM hash disclosure spoofing vulnerability exposes NTLM hashes when a user interacts with a malicious file. Simply selecting or right-clicking a file could trigger a remote connection, allowing an attacker to capture NTLM hashes for cracking or pass-the-hash attacks.   Potential for attackers to authenticate as the user, leading to unauthorized access. 

Source:  Microsoft       

In addition to the actively exploited vulnerabilities, several other critical flaws were also addressed: 

  • CVE-2025-21376: A Windows Lightweight Directory Access Protocol (LDAP) RCE vulnerability that could allow attackers to execute arbitrary code remotely. 
  • CVE-2025-21379: A DHCP Client Service RCE vulnerability that may enable remote attackers to execute code with elevated privileges. 
  • CVE-2025-21381: An RCE vulnerability in Microsoft Excel that could be triggered through malicious spreadsheet files. 

Remediation: 

  • Apply Updates: Immediately install the February 2025 Patch Tuesday updates to address these vulnerabilities. 

Conclusion: 

The February 2025 Patch Tuesday release addresses critical security vulnerabilities, including actively exploited zero-days. Timely application of these updates is essential to protect systems from potential threats. Organizations should review the affected products and implement the necessary patches and mitigations to maintain security integrity. 

The attack vector is local, meaning the attacker needs local access — physically or remotely, using SSH method without user interaction and if successful in exploiting, can give the attacker system privileges.

References: 

Security Advisory

Critical Security Updates: Microsoft Jan 2025 Patch Tuesday Fixes 8 Zero-Days & 159 Vulnerabilities 

Summary 

Microsoft has released its January 2025 Patch Tuesday updates, delivering critical fixes. Key products impacted include Windows Telephony Service, Windows Digital Media, and MSMQ, among others.

Key take away:

  • Microsoft addressed 159 vulnerabilities across multiple products, including eight zero-day flaws, with three actively exploited in the January 2025 Patch Tuesday updates.
  • Key vulnerabilities include privilege escalation flaws in Hyper-V and remote code execution bugs in Microsoft Excel.
  • This marks highest number of fixes in a single month since at least 2017.
OEM Microsoft 
Severity Critical 
Date of Announcement 2025-01-14 
No. of Vulnerabilities Patched 159 
Actively Exploited yes 
Exploited in Wild Yes 
Advisory Version 1.0 

Overview 

Critical updates were issued for Windows Hyper-V, Windows Themes, Microsoft Access, and Windows App Package Installer. The vulnerabilities include elevation of privilege, remote code execution, and spoofing attacks, impacting various systems. The patch targets a range of critical issues across Microsoft products, categorized as follows: 

  • 58 Remote Code Execution (RCE) Vulnerabilities 
  • 40 Elevation of Privilege (EoP) Vulnerabilities 
  • 22 Information Disclosure Vulnerabilities 
  • 20 Denial of Service (DoS) Vulnerabilities 
  • 14 Security Feature Bypass 
  • 5 Spoofing Vulnerabilities 

The highlighted vulnerabilities include 8 zero-day flaws, 3 of which are currently being actively exploited. 

Vulnerability Name CVE ID Product Affected Severity CVSS Score 
Elevation of privilege vulnerability  CVE-2025-21333,  CVE-2025-21334,  CVE-2025-21335 Windows High 7.8 
Elevation of Privilege Vulnerability CVE-2025-21275 Windows High 7.8 
Remote Code Execution Vulnerability CVE-2025-21186,CVE-2025-21366, CVE-2025-21395 Windows High 7.8 
Spoofing Vulnerability CVE-2025-21308 Windows Medium 6.5 

Technical Summary 

CVE ID System Affected Vulnerability Details Impact 
 CVE-2025-21333,  CVE-2025-21334,  CVE-2025-21335  Windows Hyper-V NT Kernel No information has been released on how elevation of privilege vulnerabilities in Windows Hyper-V NT Kernel Integration VSP, which allow attackers to gain SYSTEM privileges, were exploited in attacks, as they were disclosed anonymously.    Allow attackers to gain SYSTEM privileges 
  CVE-2025-21275  Windows App Package Installer Elevation of privilege vulnerability in the Windows App Package Installer, potentially leading to SYSTEM privileges.   Attackers could gain SYSTEM privileges 
 CVE-2025-21186,CVE-2025-21366, CVE-2025-21395   Microsoft Access  Remote code execution vulnerabilities in Microsoft Access, exploitable via specially crafted Access documents.   Remote Code Execution 
 CVE-2025-21308   Windows Themes Spoofing vulnerability in Windows Themes; viewing a specially crafted theme file in Windows Explorer can lead to NTLM credential theft.   NTLM credential theft 

Source:  Microsoft       

Additional Critical Patches Address High-Severity Vulnerabilities 

  • Eight of this month’s patches address Virtual Secure Mode components, requiring administrators to follow Microsoft’s guidance for updating virtualization-based security (VBS) issues. (CVE-2025-21280, CVE-2025-21284, CVE-2025-21299, CVE-2025-21321, CVE-2025-21331, CVE-2025-21336, CVE-2025-21340, CVE-2025-21370). 
  • Windows NTLM V1 Elevation of Privilege Vulnerability (CVE-2025-21311). 
  • Windows OLE Remote Code Execution Vulnerability (CVE-2025-21298). 

Remediation: 

  • Apply Updates: Immediately install the January 2025 Patch Tuesday updates to address these vulnerabilities. 
  • Disable NTLM: For CVE-2025-21308, consider disabling NTLM or enabling the “Restrict NTLM: Outgoing NTLM traffic to remote servers” policy to mitigate the risk.  
  • Exercise Caution with Untrusted Files: Avoid opening or interacting with files from untrusted sources, especially those with extensions associated with Microsoft Access. 

Conclusion: 

The January 2025 Patch Tuesday release addresses critical vulnerabilities that could allow attackers to gain elevated privileges, execute arbitrary code, or steal credentials. Prompt application of these updates is essential to maintain system security. Additionally, implementing recommended mitigations, such as disabling NTLM, can provide further protection against potential exploits. 

References: 

https://msrc.microsoft.com/update-guide/releaseNote/2025-Jan

Security Advisory

Zero-Day Vulnerability in Windows Exposes NTLM Credentials

Summary

OEM

Microsoft

Severity

Critical

Date of Announcement

2024-12-12

CVE

Not yet assigned

Exploited in Wild

No

Patch/Remediation Available

Yes (No official patch)

Advisory Version

1.0

Vulnerability Name

NTLM Zero-Day

Overview

A recently discovered zero-day vulnerability in Windows, enables attackers to steal user credentials through a malicious file viewed in File Explorer. This “clickless” exploit bypasses the need for user interaction, creating significant security risks. While Microsoft investigates, 0patch has released an unofficial micropatch to mitigate the threat. Users are advised to apply the patch or implement mitigations to reduce exposure.

Vulnerability Name

CVE ID

Product Affected

Severity

NTLM zero-day

Not Yet Assigned

Microsoft Windows

Critical

Technical Summary

CVE ID

System Affected

Vulnerability Details

Impact

Not Yet Assigned

Windows 7 to 11 (24H2), Server 2008 R2 to 2022

A zero-day vulnerability that allows NTLM credential theft by viewing a malicious file in File Explorer. The flaw forces an outbound NTLM connection, leaking NTLM hashes. Exploitation requires no user interaction beyond viewing a malicious file, which can be delivered through shared folders, USB drives, or malicious downloads in the browser's default folder.

Enables attackers to steal NTLM credentials and  gain unauthorized access of the affected systems.

Remediations

  • Apply the 0patch Micropatch:
    • Register for a free account at 0patch Central.
    • Install the 0patch agent to automatically receive the micropatch.
  • Disable NTLM Authentication:
    • Navigate to Security Settings > Local Policies > Security Options in Group Policy.
    • Configure “Network security: Restrict NTLM” policies to limit NTLM usage. 

General Recommendations

  • Only enable patches or configurations after testing them on non-critical devices to ensure minimal impact.
  • Stay updated on Microsoft’s response and the availability of an official patch through trusted news sources or Microsoft’s advisories.
  • Inform users about the risks of handling unfamiliar files and downloading content from untrusted sources.
  • Monitor systems for suspicious NTLM-related activity.

References

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