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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

Critical Windows Privilege Escalation Vulnerability with Public Exploit

Cybersecurity researchers reported a critical Windows privilege escalation vulnerability, identified as CVE-2024-43641 affecting Microsoft Windows. This flaw, which affects various editions of Windows Server 2025, Windows 10, and Windows 11, has been assigned a CVSS v3.1 score of 7.8, indicating high severity.

Summary 

OEM Microsoft 
Severity High 
CVSS 7.8 
CVEs CVE-2024-43641 
Exploited in Wild No 
Patch/Remediation Available Yes 
Advisory Version 1.0 

Overview 

A significant Windows Registry Elevation of Privilege vulnerability, identified as CVE-2024-43641, affects multiple editions of Windows. A recently released Proof-of-Concept (PoC) exploit demonstrates how attackers can exploit this flaw to gain elevated privileges. 

Vulnerability Name CVE ID Product Affected Severity 
Windows Registry Elevation of Privilege Vulnerability  CVE-2024-43641  Windows    High 

Technical Summary 

The vulnerability, CVE-2024-43641, exploits a design flaw in Windows registry hive memory management, specifically during a double-fetch process under memory pressure. This flaw allows malicious SMB servers to respond with differing data for consecutive read requests, breaking kernel assumptions and enabling privilege escalation to SYSTEM level. Key technical details are as follows: 

CVE ID System Affected Vulnerability Details Impact 
CVE-2024-43641 Windows 10, Windows 11, Windows Server 2008–2025 The vulnerability involves improper handling of registry hive memory management under memory pressure. A malicious SMB server can respond with differing data to consecutive read requests, breaking kernel assumptions. Exploitation leverages a “False File Immutability” (FFI) condition. Allows attackers to escalate privileges, execute arbitrary code, and compromise system integrity. 

Remediation: 

  • Apply Patches: Users and system administrators are strongly advised to promptly apply the latest security updates. 
  • Monitor Activity: 
  • Monitor logs for suspicious activity related to registry operations. 
  • The cybersecurity community is actively monitoring the situation for any indications of active exploitation in the wild. 

Conclusion: 

CVE-2024-43641 is a high-severity vulnerability with a publicly available PoC exploit. It is crucial to apply security patches immediately and follow best practices to mitigate the risk of exploitation. Organizations must stay alert and monitor ongoing developments to ensure complete protection against this emerging threat. 

References: 

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