January 2025 Microsoft Security Updates: Major Patch Cycle Explained

Attention Windows users! Microsoft's first batch of 2025 security updates has officially dropped, and it’s a big one. Covering a whopping range of supported Windows versions, server operating systems, Microsoft Office, and even .NET, this update cycle is a doozy—in more ways than one. As the new year kicks off, the tech giant has not held back, releasing patches for 159 security vulnerabilities spread across their ecosystem. Let’s dive into the meat and potatoes of what this means for you as a Windows enthusiast, IT professional, or curious observer.

---

Executive Summary: What’s Cooking in January 2025​

Microsoft's latest security update cycle addresses 159 vulnerabilities in Microsoft products, with two additional updates aimed at vulnerabilities in third-party software. While that sounds impressive, there are caveats. Not all upgrades will be smooth due to existing compatibility issues, particularly with Windows versions nearing their end of life. To sweeten—or complicate—things further, automatic upgrades loom for Windows versions at the end of support.
Here's the high-level breakdown:

• Products Included: Windows 10, Windows 11 (multiple versions), Windows Server (2008 R2 to 2025), and more.
• Key Highlights:
  • Windows 11 Version 22H2 and Home & Pro are officially out of support. Automatic upgrades to newer versions have begun!
  • Citrix software compatibility issues are a headache for affected setups.

Let’s explore this further across client and server systems!

---

Windows Clients: What’s New?​

Supported clients, including Windows 10 and Windows 11, see robust vulnerability patches—some critical, others important.

Windows 10 Version 22H2 & Windows 11 (22H2, 23H2, and 24H2)​

• Common Vulnerabilities Addressed (5 Critical):
  • Microsoft Digest Authentication Remote Code Execution: (CVE-2025-21294) Exploits attacks enabled via improper protocol handling.
  • SPNEGO (NEGOEX) Security Mechanism RCE: (CVE-2025-21295) A weakness directly impacting OS integrity.
  • BranchCache RCE: (CVE-2025-21296) Yes, caching could get weaponized against you!
  • Windows OLE RCE: (CVE-2025-21298) Hello, remote code exec inside your Object Linking & Embedding.
  • Reliable Multicast Transport Driver RCE: (CVE-2025-21307) Your system might be inadvertently broadcasting havoc.

Windows 11's latest version, 24H2, adds complexity. Not only does it inherit Windows 10 vulnerabilities, but it also sees exclusive patches like:

• Windows NTLM V1 Elevation of Privilege: (CVE-2025-21311). Yes, folks, NTLM is showing its age, and attackers are eager to exploit it.

Fun Fact: Many modern users don't even know half of these processes run on their machines, let alone what NTLM is. A quick explanation: NTLM stands for NT LAN Manager, a legacy authentication protocol. Simply put, it was the security of your Windows logins from the '90s...which likely explains why it's still vulnerable today!

Click to expand...

Known Issues for Windows Clients​

Think you’ll just click "Update" and call it a day? Not so fast. Keep these known issues in mind:

• OpenSSH May Fail: If you're managing remote connections through SSH, updates could halt functionality unless permissions are reconfigured. A temporary (but cumbersome) fix is provided.
• Citrix Compatibility: Systems with Citrix components may outright reject January’s update batch. No magic fix here—you’ll need to follow Citrix's workaround to smoothly transition.

---

The Server Landscape: It’s All About the Big Leagues!​

Microsoft's server products traditionally keep mission-critical systems humming. Whether you're running legacy servers like Windows Server 2008 R2 or modern heavyweights such as Windows Server 2025, there's plenty to patch this month.

Breakdown of Server Versions​

1. Windows Server 2008 R2 – On extended support, but still clinging to life with 78 vulnerabilities (6 critical) cleared. Vulnerabilities mirror client-side issues, especially remote execution exploits.
2. Windows Server 2016 & 2019 – These elder statesmen see updates for RDP RCE (CVE-2025-21309) alongside cumulative patches for older bugs.
3. Windows Server 2025 – Leading the charge into the future while patching 125 vulnerabilities, including the NTLM Elevation of Privilege problem (CVE-2025-21311).

Pro Tip: If you’re managing a server setup, always check release notes for KB codes specific to cumulative updates. Knowing what you’re downloading helps streamline patch testing.

Click to expand...

---

Exploring Update Improvements​

Microsoft’s updates this month primarily focus on:

• Closing loopholes in authentication protocols (e.g., NTLM, Digest Mechanism).
• Patching remote code execution (RCE) exploit areas.
• Enhancing .NET Framework consistency.

Still, not all updates are created equal. If you're using legacy devices, such as those running Windows 10 versions nearing end-of-support or ancient Windows Server builds, prioritize applying patches selectively rather than updating everything blindly.

---

How to Apply These Updates?​

Now, we come to the practical bit: getting these patches onto your systems efficiently.

Step-by-Step User Guide for Standard Systems:​

1. Open Start Menu → Search for “Windows Update.”
2. Hit Check for Updates.
3. Wait patiently as Microsoft scans and queues updates.
   • You may find a button prompting you to Download & Install All. Use it.
4. Reboot Securely: Updates typically require shutting down subsystems for installation. Let the PC do its thing.

Manual Downloads:​

If you enjoy living on the edge—or just don’t trust automatic updates—you can download these manually from the Microsoft Update Catalog. Look for terms like "Cumulative Update" followed by your version’s KB####### code. Manually installed updates do the same thing but in your preferred time frame.

---

Important Advisory for IT Admins​

Here are some considerations for administrators managing large deployments:

1. Testing Matters: Before rolling out KB packages across dozens of machines, apply updates to test environments!
2. End of Life Upgrades: Users of Windows 11 Home/Pro 22H2 have EoL mandates forcing automatic upgrades. Attempt early migrations where possible.
3. Citrix Coordination: Partner with your application teams to implement its workaround prior to deployment.

Tip: Utilize tools like Microsoft Intune or Windows Server Update Services (WSUS) to streamline and control rollouts.

Click to expand...

---

Final Thoughts​

Microsoft's January 2025 updates mark a robust start to the year, rolling together battle-worn culprits—hello NTLM—and introducing newer, targeted fixes for critical vulnerabilities. Yet, as always with big upgrades, compatibility and "quirks" of software ecosystems could lead to hiccups.
Bear in Mind:

• Avoid delays—even small vulnerabilities, when unpatched, become hacker playgrounds.
• For systems nearing their end of support, embrace updates as a pathway, NOT AN AFTERTHOUGHT.

What’s your experience so far with January’s patches? Are you ready to upgrade or still bracing through legacy server pain points? Let us know on the forum!

---

Source: gHacks Technology News The Windows security updates for January 2025 are now available