Windows 11's inetpub Folder: Security Fix or Hidden Vulnerability? A Complete Guide

The recent emergence of the "inetpub" folder in Windows 11 systems has stirred a mix of curiosity and concern among users and IT professionals alike. Introduced as part of Microsoft's April 2025 cumulative update, this seemingly innocuous, empty directory located at the root of the system drive (usually C:\inetpub) is more than just a leftover or a redundant folder—it plays a critical role in patching a significant security vulnerability known as CVE-2025-21204.

The Security Context of inetpub​

Traditionally, inetpub is associated with Microsoft's Internet Information Services (IIS), where it serves as the default directory for hosting websites and web applications. For most consumer users, particularly those who do not run IIS, the sudden presence of this folder has come as a surprise. Despite being empty and occupying negligible disk space, Microsoft's introduction of inetpub with the April 2025 update is a deliberate protective measure integrated into the Windows servicing infrastructure.
The CVE-2025-21204 vulnerability relates to improper handling of symbolic links (symlinks) within the Windows Update stack. Symlinks are filesystem shortcuts that can redirect operations from one file or directory to another. Improper resolution of these links can allow local attackers to manipulate system files or escalate privileges by redirecting update operations to malicious targets.
To combat this, Microsoft created a hardened and trusted folder—inetpub—on every system, ensuring that the servicing stack, running with SYSTEM privileges, has a safe, controlled directory to interact with when staging files during updates. By securing this directory and granting it strict permissions, Microsoft aimed to close the gap that attackers previously exploited through missing or improperly secured directories.

How the inetpub Folder Becomes a Vulnerability​

Ironically, the security fix itself introduces a new vulnerability stemming from how Windows treats the inetpub directory. The servicing stack treats the inetpub folder as trusted but fails to validate whether it is a regular folder or has been replaced or redirected by a directory junction (a type of symbolic link in Windows).
Security researcher Kevin Beaumont uncovered that any non-admin user with local access can exploit this by replacing the inetpub folder with a directory junction via a simple command like:
mklink /J C:\inetpub C:\Windows\System32\notepad.exe
This command creates a junction pointing inetpub to a system file (e.g., Notepad.exe). When Windows Update later tries to write to inetpub, it is misdirected to this file path, causing update failures or rollbacks.
Because the servicing stack runs as SYSTEM and implicitly trusts C:\inetpub, it does not check the ownership or type of this directory, enabling local users—even without admin privileges—to cause Windows Update attempts to fail. This results in a denial-of-service-type vulnerability where security patches cannot be applied until the situation is corrected.

Implications for Users and System Security​

This vulnerability represents a peculiar and troubling dynamic where the fix for one vulnerability (CVE-2025-21204) inadvertently opens the door for another attack vector: easy sabotage of Windows Update by low-privilege users. The impact is particularly serious for organizations relying on timely security patches to maintain compliance and defend against malware.
From an administrative perspective, the core risk is not immediate remote exploitation but the local user's ability to halt critical system updates without requiring admin rights. Environments with many shared or multi-user Windows machines—including enterprises, public labs, and educational institutions—must be aware of this attack surface.

Mitigating the Vulnerability​

At the time of discovery, Microsoft has not provided a dedicated patch or official fix beyond the existing update. In the interim, security professionals and power users can manually modify the permissions on the inetpub folder to mitigate the risk:

• Restrict Write and Delete Permissions: Remove write and delete permissions for all non-system user accounts on the inetpub folder.
• Allow Only SYSTEM and TrustedInstaller Full Control: Grant full control permissions solely to the SYSTEM account and NT SERVICE\TrustedInstaller.
• Disable Inheritance: Disable permission inheritance on the folder and remove all inherited permissions to ensure only explicitly allowed accounts have access.

These steps effectively block any non-admin process—including malicious or careless users—from substituting the folder with a malicious junction, preserving update functionality. If issues arise with Windows Update after the permission changes, resetting Windows Update components or restoring default permissions can help resolve them.

Correct Handling of inetpub​

In addition to restricting permissions, users are strongly advised:

• Not to delete the inetpub folder, as its presence is essential for the security patch to work correctly.
• If the folder has been deleted, restore it by temporarily enabling IIS through the Control Panel's "Turn Windows features on or off" dialog. This process recreates the folder with proper permissions.
• Alternatively, uninstalling and reinstalling the relevant April 2025 update achieves the same restoration.

Broader Lessons and Context​

The inetpub case exemplifies an ongoing pattern in Windows security updates: patches often introduce complex, under-the-hood changes that are pivotal for security but may appear puzzling or useless at first glance. Empty folders like inetpub, or subtle permission modifications, serve as silent sentinels guarding Windows's integrity.
Yet, this also highlights the challenges in patch design where an update must balance protecting critical system operations while limiting potential new attack vectors—particularly from low-privilege, local users. The design oversight in ignoring directory junction validations during servicing stack operations is a stark reminder of the delicate and sometimes paradoxical nature of security engineering.
For IT teams and individual users, cautious management of system updates and ongoing vigilance through monitoring folder permissions and unexpected symbolic links can prevent exploitation of such vulnerabilities while awaiting a formal Microsoft fix.

Conclusion​

The unexpectedly empty inetpub folder on Windows 11 systems is no mere bystander; it is a deliberate security tool embedded within the latest updates to patch a dangerous symbolic link vulnerability. However, its role as a trusted directory introduces a novel attack vector exploitable by local users to disrupt Windows Update processes.
Until an official patch arrives, manual tightening of folder permissions offers a practical defense. Users should keep the inetpub folder intact and maintain regular update cycles, bearing in mind the increasingly sophisticated and sometimes subtle nature of Windows security measures.
In the evolving landscape of OS security, even an empty directory can wield considerable influence over your system’s resilience, underscoring the need for informed stewardship of updates and system assets.

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This analysis draws extensively on findings documented by security researcher Kevin Beaumont and a range of technical discussions throughout Windows enthusiast communities, alongside Microsoft’s official guidance on the inetpub folder’s purpose and handling .

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Source: Windows 11's New Inetpub Folder is Hackable. Try This Temporary Fix - Make Tech Easier

 

[ChatGPT]

The inetpub folder, which many Windows users traditionally associated exclusively with web servers running Microsoft’s Internet Information Services (IIS), recently gained an entirely new and somewhat controversial role in Windows security management. Starting with the April 2025 cumulative Windows 11 update, this seemingly innocuous directory began appearing on virtually all updated systems, regardless of whether IIS was installed or running. Far from being a mere leftover from server setups, the inetpub folder is now central to a significant security hardening effort addressing a particular Windows vulnerability. However, what was intended as a fix has introduced fresh complications and vulnerabilities, leaving both users and administrators grappling with the implications.

The Background: What Is the Inetpub Folder?​

Historically, inetpub is the base directory where IIS stores its web content, logs, and scripts. Ordinarily, systems without IIS would not contain this folder. However, with the introduction of the April 2025 update (notably Windows 11 update KB5055523 and its Windows 10 counterpart), Microsoft began forcibly creating an empty inetpub folder on the system drive (typically C:\inetpub). This move puzzled many users who neither run IIS nor host any web services, sparking confusion and concern.
Microsoft clarified that the inetpub folder’s existence is deliberate and forms a key component of the mitigation against a specific security vulnerability, identified as CVE-2025-21204. This vulnerability deals with improper handling of symbolic links (symlinks) within the Windows Update servicing stack and other critical system operations. Symbolic links are filesystem references that point to other files or directories, potentially enabling redirection of file access if mishandled.
The umpteenth irony here is that an empty, unused folder commonly associated with web services has been repurposed as a security feature — a proactive “digital moat” intended to prevent attacks that exploit symlink mismanagement. Even though the inetpub folder remains unused by the user, it serves as a controlled sandbox, preventing localized privilege escalation attacks that rely on symlink tricks.

The Vulnerability Exposed: How the Inetpub Folder Became Hackable​

While the inetpub folder was introduced to plug a significant security hole, security researcher Kevin Beaumont uncovered a critical issue: the folder itself can be exploited — without needing administrator privileges — to subvert Windows Update and potentially other core system functions.
The root of the problem lies in how Windows Update’s Servicing Stack handles this directory. The servicing stack operates with SYSTEM privileges and assumes that C:\inetpub is a safe location, trusting its existence and contents implicitly. However, it does not verify whether this folder is a normal directory or has been replaced by a directory junction (a powerful type of reparse point in Windows that redirects filesystem operations).
Using a single command—specifically mklink /J C:\inetpub C:\Windows\System32\notepad.exe or pointing elsewhere—any local non-admin user can replace the folder with a directory junction. This tricks the servicing stack into misdirecting file operations to an unintended target, such as system executables or other critical files. The immediate consequence is that Windows Update operations targeting inetpub fail or roll back.
This vulnerability dramatically lowers the bar for sabotage because it doesn’t require admin rights or advanced tools. Any user with command-line access can manipulate the junction and cause updates to fail silently, leading to patch rollbacks and potential exposure to security risks this patch was designed to fix. This form of exploitation highlights a broader Windows security challenge: non-admin users wielding permissions that allow dangerous filesystem tricks that disrupt system integrity.

Consequences and Real-World Impact​

For large organizations, especially those with multi-user environments or shared machines, this vulnerability poses a serious risk. Attackers or malicious insiders with basic user rights could halt system updates, allowing malware to persist unpatched or regulatory compliance to lapse without straightforward detection.
The result is an ironic twist: a patch intended to prevent privilege escalation and symlink abuse introduces a new pathway for low-privilege users to block or sabotage system updates. Error messages from Windows Update tend to be vague and unfriendly to administrators trying to diagnose the problem, compounding troubleshooting challenges.
Microsoft's silence since the discovery of this vulnerability has left IT administrators and security professionals struggling to devise workaround measures, underscoring a frustrating aspect of the modern Windows security ecosystem, where patching often resembles a game of whack-a-mole.

Temporary Workaround: Securing the Inetpub Folder Permissions​

Until Microsoft releases an official fix, users and administrators can apply permissions hardening to the inetpub folder to mitigate this risk. The core principle behind this workaround is to restrict write and delete operations on C:\inetpub to highly trusted system accounts—namely SYSTEM and TrustedInstaller—while stripping these permissions from all regular user accounts, including administrators.
The procedure is straightforward:

• Right-click the inetpub folder on the C drive and select Properties.
• Navigate to the Security tab and click Advanced.
• Click the Disable inheritance button and choose to Remove all inherited permissions.
• Click Add, then select Principal.
• Enter SYSTEM, set Full control, and confirm.
• Repeat for NT SERVICE\TrustedInstaller, giving it Full control as well.
• Apply the changes and exit.

This setup effectively blocks any process running under non-system accounts from replacing the inetpub folder with a directory junction, preserving the integrity of Windows Update operations.
If needed, this can be reversed by re-enabling inheritance and removing the manually added principals.

Why Microsoft’s Approach Is Symptomatic of Larger Security Challenges​

The inetpub folder saga is emblematic of the recurring tension in Windows security: patching underlying flaws often requires complex filesystem or permission constructs that, if handled imperfectly, can spawn new vulnerabilities.
Most concerning is Microsoft’s silence on the vulnerability and lack of an imminent fix, leaving crucial security update pipelines vulnerable to interruption on millions of systems. Beyond the technical issues, this episode reminds us of the precarious status quo for system security—where defense mechanisms rely heavily on filesystem-based trust assumptions and lack robust internal validation.
Moreover, the ease with which non-admin users can subvert system internals through something as deceptively simple as directory junction manipulation highlights the persistent risk of “user rights gone rogue,” a known but stubborn challenge in Windows security.

Practical Advice for Users and Administrators​

For typical users, the presence of an empty inetpub folder is no cause for alarm; it is part of the OS’s protective fabric. Users should avoid deleting or altering this folder.
For IT administrators and power users managing Windows devices:

• Apply the described permissions lockdown on inetpub to guard against junction attacks.
• Monitor Windows Update logs for cryptic errors that might indicate junction-related sabotage.
• Be prepared to restore the folder or permissions if Windows Update components appear stuck.
• Stay updated with Microsoft’s security advisories and expect a more permanent patch in future cumulative updates.
• Educate users about the risks of unnecessary folder manipulation.

In case the inetpub folder was deleted, Microsoft recommends restoring it by enabling and then disabling IIS via “Turn Windows features on or off.” This re-creates the folder with the necessary security context.

Broader Implications: The Inetpub Folder as a Case Study in Modern Windows Security​

This incident underscores the growing complexity of modern Windows security, where “invisible” folders and permissions setups play crucial defensive roles. The inetpub folder, once a quiet bastion of IIS content, now stands as an unintended gateway to security vulnerabilities, a microcosm of the challenges in balancing usability, legacy features, and robust defense.
It also stresses the importance of transparent communication between vendors and users. Microsoft’s delayed and limited communication left many users confused or exposed, raising calls for better documentation and proactive transparency.
Finally, it reflects an evolution in Windows security: patches increasingly rely on nuanced filesystem controls, symbolic link protections, and service account configurations—layers only meaningful to advanced users and security teams but critical in countering sophisticated local threat vectors.

Conclusion​

The inetpub folder’s new role as both a security feature and a vulnerability highlights the complex balancing act Microsoft faces in protecting Windows systems. While the folder is essential for patching a serious flaw, its current exploitable state by non-admin users represents a fresh attack vector that demands urgent attention.
Until Microsoft rolls out a definitive fix, administrators should take proactive measures to secure the inetpub directory permissions, thwarting trivial user exploits while ensuring Windows Update continues unhindered.
This episode stands as both a cautionary tale and a window into the dynamic, intricate world of contemporary Windows security—where empty folders can be silent guardians or gateways for exploitation, and where every update can reshape the landscape in surprising ways.

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References:

• Original research and community findings on inetpub folder vulnerabilities and Windows Update exploits as documented by security researcher Kevin Beaumont and various Windows community sources.
• Official Microsoft security advisories on update KB5055523 and CVE-2025-21204.
• Practical guidance on fixing inetpub folder permissions to prevent junction point abuse.

These insights are synthesized with commentary and analysis based on detailed investigations published on WindowsForum.com and MakeTechEasier .

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Source: Windows 11's New Inetpub Folder is Hackable. Try This Temporary Fix - Make Tech Easier

 

[ChatGPT]

The sudden appearance of the "inetpub" folder on Windows 11 systems following the April 2025 cumulative update has sparked substantial discussion about both its purpose and security implications. For many users, stumbling upon an empty folder named "inetpub" on the root of their C drive naturally raises suspicion, especially considering that this directory is traditionally associated with Microsoft's Internet Information Services (IIS) used for web hosting. However, Microsoft's explanation reveals that this folder's presence is neither accidental nor indicative of any rogue activity. Rather, it is a deliberate security feature aimed at patching a critical vulnerability—CVE-2025-21204—in Windows' handling of symbolic links within the update mechanism.

The Security Context Behind inetpub Creation​

The core issue addressed by the April 2025 update revolves around Windows Update's servicing stack and its incorrect handling of symbolic links (symlinks). Cyber attackers can exploit symbolic link vulnerabilities by planting malicious symlinks that redirect file operations to unintended locations, enabling privilege escalation or unauthorized modification of crucial system files.
Microsoft addressed this by ensuring that every updated Windows system now contains a secured, empty "inetpub" folder. This folder acts as a hardened, controlled environment with strict permissions, preventing malicious manipulations via symbolic links in the update process. By creating a trusted directory with SYSTEM and TrustedInstaller exclusive control, Windows Update's servicing stack can reliably stage files without the risk of being fooled by directory junctions or other reparse points disguised as legitimate folders.
This folder, although empty, essentially serves as a "decoy" or safe containment area. It is not to host any web content unless IIS is intentionally enabled, but rather exists strictly as part of the protective infrastructure designed to prevent exploitation of the symbolic link vulnerability.

The Exploit: How the inetpub Folder Can Be Manipulated​

Ironically, the same folder introduced to patch a symbolic link vulnerability has itself become an avenue for potential exploitation. Security researcher Kevin Beaumont uncovered that any local user, even without administrative privileges, can exploit this setup by replacing the "inetpub" folder with a directory junction (a more potent form of symlink). Using a simple command such as:
mklink /J C:\inetpub C:\Windows\System32\notepad.exe
an attacker can reroute what Windows Update sees as the "inetpub" directory to an arbitrary file or location. Since the servicing stack runs with SYSTEM privileges and considers "inetpub" a trusted directory, it does not validate whether this is indeed a real folder or a junction to another location, nor does it verify ownership properly.
As a result, Windows Update operations performed on this redirected junction fail or rollback, effectively disabling security updates without raising clear alarms. This easy-to-execute technique requires no admin rights, lowering the barrier for local attackers to disrupt updates and potentially open the system to further compromise if unpatched.
The implications here are significant: in shared or less-secure computing environments, an unauthorized local user could halt security patches and impede system integrity, increasing exposure to malware and exploits.

Why Microsoft's Approach is Both Innovative and Problematic​

Microsoft's introduction of the empty "inetpub" folder represents a classic security-by-design maneuver. By preemptively placing a known, controlled directory to contain update operations, they mitigate risks arising from missing directories that attackers might otherwise exploit with symlinks.
This approach embraces complexity by integrating structural defenses directly into filesystem hierarchy, protecting update mechanisms from "link following" attacks. It is a pragmatic solution balancing the need for security and backward compatibility without large-scale changes to trusted system components.
However, the downside lies in rigidity and assumptions. The servicing stack’s failure to check for junctions or ownership points to incomplete validation logic. The fact that non-admin users can hijack this folder to break updates reveals a flaw in this otherwise elegant fix. Security experts characterize this as patching one vulnerability only to introduce another vector for disruption.
Moreover, Microsoft's silence and slow response following disclosure exacerbate concerns. Administrators are left with no official fix or mitigation other than manual permissions adjustments on a system-critical folder—a temporary and potentially disruptive workaround.

Mitigating the Vulnerability: Practical Steps for Users​

Until Microsoft addresses this vulnerability directly in an update, users and IT professionals can apply a practical mitigation by restricting write and delete permissions on the "inetpub" folder. Since creating junctions requires such permissions on the parent directory, blocking non-system users from modifying "inetpub" can prevent the exploit:

• Locate the inetpub folder in the root of your system drive (typically C:\inetpub).
• Right-click the folder and open Properties.
• Navigate to the Security tab and click on Advanced.
• Disable inheritance by clicking Disable inheritance and choosing Remove all inherited permissions.
• Add permissions explicitly for the system accounts only:
• Add SYSTEM with Full Control
• Add NT SERVICE\TrustedInstaller with Full Control
• Confirm and apply changes.

This setup ensures no user, including administrators, can replace the folder with a junction point, but legitimate system processes like Windows Update still have full access.
If at any point issues occur with Windows Update, resetting Windows update components or reverting the permissions to inherit defaults can be done to restore normal behavior.
This interim fix effectively neutralizes the current vulnerability while allowing updates to proceed normally, although it requires users to carefully manage permissions and monitor update success.

Broader Reflections: What This Means for Windows Security and Users​

The "inetpub" folder episode exemplifies ongoing challenges in modern Windows security. While Microsoft attempts to shore up vulnerabilities rapidly, the overlapping layers of updates, patches, and system services occasionally interact in unforeseen ways.
Key takeaways include:

• Security Complexity: As Windows evolves, so do the underlying assumptions and interdependencies in system components. Small changes like an empty folder can ripple into significant security concerns.
• Local Attack Surface: The fact that a non-admin user can disrupt crucial updates underscores the persistent risks of local access in modern environments—be it from insiders, shared devices, or malware exploiting delegated permissions.
• User Awareness and Control: For everyday users and IT admins alike, awareness of such lurking issues is critical. Blindly deleting unknown folders (like inetpub) could compromise security patches, while allowing unrestricted access risks exploitation.
• Microsoft's Communication and Response: Transparent, timely advisories from Microsoft are essential to manage such vulnerabilities. Users benefit from clear guidance and official fixes rather than piecemeal community workarounds or silence.

Ultimately, the "inetpub" folder story is a reminder that cybersecurity is a dynamic domain where fixes against one threat can sometimes create new challenges. Vigilance, layered defense, and informed user behavior remain as crucial as ever.

How to Handle the inetpub Folder Safely​

Users should:

• Never delete the inetpub folder: Despite seeming useless for most users, its removal disables part of the critical Windows Update protection.
• Restore the folder if deleted by enabling IIS briefly via Control Panel > Programs > Turn Windows features on or off. This action recreates the folder with proper permissions. Afterward, IIS can be disabled without removing the folder.
• Maintain folder permissions as recommended to prevent unauthorized modification.
• Keep Windows updates current, as Microsoft may fix this vulnerability in future patches.

These simple measures preserve both security integrity and system functionality while minimizing risk from the current exploit vector.

Conclusion​

The creation of the "inetpub" folder in the April 2025 Windows update is a well-intended security feature designed to protect against a severe symbolic link vulnerability within the Windows Update servicing stack. However, this protective folder itself can be exploited by non-admin users to disrupt critical updates, leading to a paradoxical security hole.
Until Microsoft issues a permanent fix, users must implement permission-based workarounds to safeguard their systems. This case reflects the intricate and sometimes ironic complexity of contemporary Windows security strategies, where even an empty folder can be both guardian and gatekeeper—and, potentially, a vulnerability.
Staying informed, cautious with system modifications, and proactive about applying updates and permissions is the best defense users can mount in this evolving landscape of digital security.

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References:

• Analysis of inetpub folder’s role and vulnerability by Kevin Beaumont and community experts
• Microsoft’s advisory on inetpub folder and CVE-2025-21204
• User instructions for permissions adjustment and IIS-related folder restoration
• Commentary and implications on Windows update and security complexity

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Source: Windows 11's New Inetpub Folder is Hackable. Try This Temporary Fix - Make Tech Easier

 

[ChatGPT]

The Windows "inetpub" folder, a long-standing directory primarily associated with Microsoft's Internet Information Services (IIS), has recently become the center of a significant security discussion following the April 2025 cumulative update for Windows 11. Its sudden appearance on virtually all Windows 11 systems—even those without IIS enabled—has raised eyebrows and sparked important conversations about Windows security, update mechanisms, and the unintended consequences of patch fixes.

The Security Origin of the inetpub Folder​

Traditionally, the "inetpub" folder serves as the root directory for IIS web services—the place that hosts web pages, logs, scripts, and mail service files. However, starting with the April 2025 update (notably KB5055523 and related patches), Microsoft began creating an empty "inetpub" directory on the root of the C: drive across Windows 11 systems regardless of IIS usage.
Why? This was a deliberate security strategy and not a bug or leftover directory. It addresses a critical vulnerability identified as CVE-2025-21204, which involves improper handling of symbolic links (symlinks) within the Windows Update servicing stack. Symlinks are filesystem objects that act as pointers or shortcuts to other files or directories. The vulnerability allowed local attackers with physical or user access to misuse symlinks to escalate privileges or corrupt system files in the Windows update mechanism.
The new "inetpub" folder acts as a controlled environment and a protective container designed to thwart symlink-based attacks. By forcing Windows Update and associated processes to stage files in a system-controlled and benign directory (even if empty), Microsoft sought to add a layer of defense against exploitation through malicious link manipulation. Crucially, the folder is created with system-level, locked-down permissions to prevent unauthorized modifications, fortifying this safeguard layer.
Microsoft has explicitly warned users not to delete the "inetpub" folder, even if IIS is unused. Deletion could break the security patch and expose the system to the vulnerabilities the folder helps prevent. For users who accidentally delete it, the recommended fix is to re-enable IIS temporarily via Windows Features, which recreates the folder with the correct permissions, or alternatively reinstall the security updates that contain the patch.

A New Attack Vector: Exploiting inetpub with Directory Junctions​

While the creation of "inetpub" was intended as an improvement, security researchers soon uncovered a new risk introduced by this very folder. The issue lies in Windows' handling of directory junctions (a type of reparse point or symlink). Specifically, any local user—even without administrator privileges—can create a junction point that replaces or redirects the "C:\inetpub" folder to point elsewhere.
For example, an attacker could execute a command like:
mklink /J C:\inetpub C:\Windows\System32\notepad.exe
This replaces "inetpub" with a junction pointing to an unrelated system file such as Notepad.exe. Because the Windows Servicing Stack runs with SYSTEM privileges and assumes "inetpub" is a trusted directory, it fails to properly check for junction points or ownership during updates. When it attempts to stage files in this redirected path, the update process can fail or roll back, effectively blocking crucial Windows updates.
This means low-privileged users can cause Windows Update to break by exploiting the "inetpub" junction, leading to denial of service on update functionality. The absurdity is striking: a patch meant to fix a security flaw inadvertently introduced a new attack surface accessible to non-admin users.

Why This Matters​

The hijacking of the "inetpub" folder using junction points is significant for several reasons:

• Ease of Exploitation: Non-admin users can easily run the mklink command to hijack "inetpub," requiring no advanced privileges or hacking tools.
• Impact on Updates: Compromising update functionality can leave the system unpatched, vulnerable to further exploits, and out of compliance with organizational security standards.
• Low Barrier to Entry: The vulnerability can be exploited by anyone with local access, including low-level users, interns, or even malware executed under non-elevated permissions.

Enterprises, IT professionals, and security-conscious users must be aware that the security patch controlling the "inetpub" folder is not a "set it and forget it" solution. It opens a new vector for local denial-of-service attacks on Windows Update — a critical functionality for system security.

Mitigating the Vulnerability: Protecting the inetpub Folder​

Until Microsoft provides an official fix addressing the directory junction bypass, users and administrators can take preventive steps to secure the "inetpub" folder permissions manually. The key is to prevent non-system users, including administrators, from having write or delete permissions on "C:\inetpub," while ensuring that SYSTEM and the TrustedInstaller service retain full control—this preserves legitimate Windows update functionality.
A recommended approach is:

• Right-click the "inetpub" folder in the C: drive and select Properties.
• Go to the Security tab, then click Advanced.
• Click Disable inheritance and choose to Remove all inherited permissions.
• Add explicit permissions back for:
• SYSTEM: Full Control
• NT SERVICE\TrustedInstaller: Full Control
• Remove any entries granting standard users or administrators write/delete permissions.
• Confirm and apply changes.

This setup blocks the ability of any non-system process, including non-admin users, to create malicious junctions or manipulate "inetpub."

Reversing Permission Changes and Troubleshooting​

If this restriction causes unexpected Windows Update failures, users can:

• Reset Windows Update components using troubleshooting commands or built-in tools.
• Restore original permissions by enabling inheritance on the "inetpub" folder and removing manually added entries.
• If necessary, reinstall the Windows update that created the folder to reset permissions.

These steps allow flexibility while lowering the risk of exploitation.

What this Means for Windows Users and IT Professionals​

The "inetpub" folder saga is a case study in modern OS security complexities. Microsoft patched one vulnerability but introduced another — illustrating the dynamic and sometimes paradoxical nature of patch management.
Key insights include:

• Security patches can introduce unexpected side effects or new attack surfaces, especially when legacy features intersect with automatic updates.
• Being proactive about local permissions and user rights remains crucial; non-admin user capabilities should be carefully controlled.
• Monitoring unusual junctions or symbolic links in critical directories could form part of an enterprise security posture.
• Clear communication from vendors like Microsoft on such changes is vital to manage user expectations and reduce confusion.

The inetpub folder, empty though it may seem, reflects larger trends: Windows is becoming a layered security environment, where even empty folders are sentinels.

Conclusion​

The addition of the "inetpub" folder in Windows 11’s April 2025 update symbolizes Microsoft's approach to counteracting sophisticated Windows Update vulnerabilities. It acts as a protective container guarding against symbolic link exploits. However, it also inadvertently exposed a junction-point vulnerability enabling non-admin users to sabotage Windows updates by redirecting the folder.
While Microsoft has not yet released a fix addressing the junction attack vector, users can mitigate risk effectively by restricting folder permissions to SYSTEM and TrustedInstaller only.
In this interplay of patches and exploits, the inetpub folder stands as both a guardian and a cautionary tale: it reminds us that security in modern OSes is a continuous, iterative battle—sometimes involving the simplest elements in unexpected ways.
For Windows users and IT professionals, vigilance, permission management, and patience remain key in navigating this evolving landscape of security and stability risks.

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This article synthesizes community findings and expert analysis from the recent WindowsForum discussions and security research insights surrounding the inetpub folder vulnerabilities and defenses.

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Source: Windows 11's New Inetpub Folder is Hackable. Try This Temporary Fix - Make Tech Easier