January 2025 Patch Tuesday: Windows 10 & 11 Security Updates and Fixes

Microsoft has kicked off 2025 with its monthly Patch Tuesday updates, and this round of fixes and improvements focuses on patching security vulnerabilities and enhancing system reliability for Windows 10 and Windows 11 users. Whether you're a casual user or a system admin responsible for critical infrastructure, these updates are worth your attention.
Let’s break down the key changes, what they address, and dive into the broader implications of this monthly maintenance ritual in the Microsoft ecosystem.

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Why January 2025 Patch Tuesday Matters​

Patch Tuesday, held on the second Tuesday of each month, is Microsoft’s way of addressing vulnerabilities, squashing bugs, and keeping systems up-to-date for millions of devices. In today's digital age—where attackers are always hunting for cracks in security—installing these updates isn’t just good housekeeping; it's critical defense.
For January 2025, Microsoft’s patches cater to both Windows 10 and Windows 11, addressing several vulnerabilities and building on features already introduced in earlier cumulative updates. Here's what they've delivered:

Regular Maintenance Plus a Security Focus​

1. Security Gaps Closed: These updates patch security loopholes in key components: Windows Defender, BitLocker, Windows Kernel, .NET Framework, and File Explorer, among others.
2. Bring-Your-Own-Vulnerable-Driver (BYOVD) Protections Expanded: BYOVD attacks are a growing trend where attackers exploit legitimate drivers to bypass security measures. Microsoft is tackling this head-on by growing its database of vulnerable drivers so they can be proactively blocked.

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Updates for Windows 10​

If you're still using Windows 10, here’s what you need to know about the latest updates:

Support for Latest Versions​

Microsoft continues to maintain multiple versions of Windows 10—albeit with some older editions approaching End-of-Support status. For this Patch Tuesday, the following versions received updates:

• Version 21H2, 22H2
  • Update Name: KB5049981
  • Build Number: 19044.5371 and 19045.5371
  • Addresses vulnerabilities and adds quality improvements from previous updates (e.g., December 2024’s KB5048652).
• Version 1809
  • Update Name: KB5050008
  • Build Number: 17763.6775
• Server Updates for Enterprise Users:
  • Windows Server 2016: KB5049993 (Build 14393.7699)
  • Version 1507: KB5050013 (Build 10240.20890)

Noteworthy Fixes​

The updates continue to enhance the performance and security of Windows 10. Improvements range from kernel security tweaks to better handling of system recovery features critical for enterprise users.

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Updates for Windows 11​

Windows 11, which offers a sleeker interface along with enhanced system security compared to its predecessor, also gets its share of updates this month. Here's the breakdown:

Key Versions Patched​

• Windows 11 (version 24H2)
  • Update Name: KB5050009
  • Build Number: 26100.2894
• Windows 11 (versions 22H2 & 23H2)
  • Update Name: KB5050021
  • Build Numbers: 22621.4751 and 22631.4751

Highlights for Windows 11​

1. Improved BYOVD Attack Mitigation: Windows 11 continues to build on its security-first ethos by expanding protection against BYOVD exploits. These attacks leverage legitimate (but now unsafe) drivers to infiltrate systems. This patch blocks those drivers effectively.
2. Servicing Stack Updates (SSUs):
   • Build numbers: 22621.4740 and 22631.4740.
   • Servicing Stack Updates ensure that your system's mechanism for receiving patches is robust and future-proof. Regular SSU enhancements help avoid issues like failed updates or installation loops.

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What Exactly Was Patched? Vulnerabilities and Security Changes​

This month’s updates tackle vulnerabilities in:

• Windows Defender: Enhanced security features in Defender, Microsoft’s built-in antivirus solution, to thwart growing malware threats.
• BitLocker: Fixes target edge cases where encryption could fail under specific configurations.
• Windows Registry & File Explorer: Addressed bugs that could expose sensitive operating system components.
• Kernel Exploits: Improved defenses against attempts to escalate privileges using Windows’ core system kernel.
• Office Suite: Updated patches for Office underline Microsoft’s wider ecosystem approach to cybersecurity.

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Getting the Updates​

Microsoft offers a variety of ways to grab these fixes:

1. Windows Update Functionality: Navigate to Settings > Update & Security > Windows Update and click “Check for updates.”
2. Microsoft Update Catalog: Advanced users or system admins can manually download patches from Microsoft's catalog.
3. Windows Server Update Services (WSUS): Businesses relying on WSUS can synchronize and deploy updates across networks.
4. Command Prompt Using WinVer: Curious about your version? Press Windows + R and type winver to see your current build.

Pro Tip: Remember to install any older Servicing Stack Update (SSU) if prompted—this helps smoothen the installation of cumulative updates like these.

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Don’t Delay: The Risks of Skipping Updates​

Why do these updates matter? Because cyber threats evolve daily. Unpatched vulnerabilities in widely-used systems like Windows 10 or 11 attract malicious actors like moths to a flame.
Take BYOVD attacks, for instance: attackers sneak their payload using outdated legitimate drivers. Without Microsoft updating its blocklist to stop these tools in their tracks, such exploits could compromise unsuspecting users.
Furthermore, updates like SSUs ensure your system stays ready for future patches, making this month’s work a crucial building block for the next roadmap of fixes.

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Final Thoughts: A Crucial Patch Tuesday​

January 2025’s Patch Tuesday serves as another reminder of why regular updates are both a chore and a necessity. Microsoft is treading familiar territory, fixing long-standing vulnerabilities while addressing newer ones like BYOVD risks.
While OS-level improvements like kernel updates and BYOVD defenses may not grab headlines, they represent Microsoft’s ongoing battle to create the safest environment possible for both consumers and enterprise users.
Have thoughts about the updates or run into patches that solved or worsened your Windows experience? Sound off in the comments! Whether you're getting WorkFromHomeTech vibes or managing business endpoints, let’s discuss how Patch Tuesday impacts us all.

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Source: Research Snipers All about Microsoft Patchday January 2025