inetpub Archives

Winsage

April 30, 2025

A mysterious new Windows 11 folder appeared – and now there’s a new exploit

Windows 11 users encountered the "inetpub" folder after the April 2023 update (KB5055523), which is a crucial component for addressing the security vulnerability CVE-2025-21204. Microsoft stated that the folder should not be removed, as it helps manage Windows Update security vulnerabilities by preventing unauthorized control through symbolic links. However, cybersecurity expert Kevin Beaumont revealed that the same patch introduced a new vulnerability that could allow remote exploitation, prompting Microsoft to acknowledge this issue with a "Moderate" status and indicate that a fix is forthcoming. Users are advised to keep their systems updated and not delete the "inetpub" folder. If the folder is deleted, it can be restored by enabling Internet Information Services in the Control Panel.

Winsage

April 27, 2025

New Security Warning After 1 Billion Windows Users Told Do Not Delete

Microsoft's recent security update for Windows has raised concerns among users due to the introduction of a new vulnerability. The update, intended to address the CVE-2025-21204 vulnerability, inadvertently created a folder named inetpub, which Microsoft claims is essential for user protection. Security researcher Kevin Beaumont has warned that this update has introduced a denial of service vulnerability that allows non-admin users to halt future Windows security updates. Microsoft has classified the issue as moderate in severity and suggested that deleting the inetpub symlink and retrying the update may resolve the problem. The report has been forwarded to the Windows security team for potential further action.

Winsage

April 25, 2025

Windows “inetpub” security fix can be abused to block future updates

A recent Microsoft security update has created a new 'inetpub' folder in the root of the system drive, linked to a fix for a Windows Process Activation elevation of privilege vulnerability (CVE-2025-21204). This folder has appeared on systems without Internet Information Services (IIS) installed. Microsoft advises users not to delete the folder, as it enhances system protection. However, cybersecurity expert Kevin Beaumont has shown that the 'inetpub' folder can be manipulated by non-administrative users to create a junction that redirects to a Windows file, potentially obstructing future Windows updates and resulting in a 0x800F081F error code. Microsoft has classified this issue as "Medium" severity and has closed the case, indicating it may be addressed in future updates.

Winsage

April 25, 2025

Microsoft’s Patch for Symlink Vulnerability Introduces New Windows Denial-of-Service Flaw

In early April 2025, Microsoft addressed a security vulnerability (CVE-2025-21204) related to symbolic links in the Windows servicing stack, specifically affecting the c:inetpub directory used by Internet Information Services (IIS). The updates created the c:inetpub folder with appropriate permissions to mitigate risks. However, this fix introduced a new denial-of-service (DoS) vulnerability, allowing non-administrative users to create junction points on the c: drive, disrupting the Windows Update mechanism. A command such as "mklink /j c:inetpub c:windowssystem32notepad.exe" could be used to exploit this flaw, preventing systems from receiving future security patches. As of April 25, Microsoft had not released a patch or acknowledged the issue, leaving systems vulnerable and emphasizing the need for monitoring user permissions and manually removing suspicious symlinks.

Winsage

April 24, 2025

Microsoft mystery folder fix might need a fix of its own

Microsoft's recent patch for CVE-2025-21204 inadvertently reintroduced the inetpub folder at c:inetpub as part of its mitigation strategy, raising concerns among system administrators. Security researcher Kevin Beaumont discovered that this folder created a new vulnerability when he used the mklink command with the /j parameter to redirect the folder to a system executable (notepad.exe). This allowed standard users to prevent Windows updates without administrative rights, as the command could be executed on default-configured systems. Beaumont has notified Microsoft of this vulnerability, but the company has not yet responded.

Winsage

April 24, 2025

An empty folder in Windows that «cannot be deleted» can permanently block OS updates

The inetpub folder, introduced in the April update of Windows 11 (version 24H2) as part of a fix for the CVE-2025-21204 vulnerability, has raised concerns among security researchers. It can be manipulated to block Windows updates without administrative rights by creating a symbolic link to notepad.exe, which can lead to a rollback of patches and leave the system vulnerable. Microsoft has not yet responded to this issue, and the possibility of a patch to address the new vulnerability is still open.

Winsage

April 24, 2025

Microsoft security patch opens up new security vulnerability

Microsoft's recent update aimed at fixing a security vulnerability (CVE-2025-2104) has unintentionally created an "inetpub" folder on the system drive of Windows operating systems. This folder's creation has raised concerns among IT security researchers, particularly Kevin Beaumont, who warns that it could lead to issues with Windows updates. Users can create junctions that redirect to the "inetpub" folder, potentially causing failures in installing updates and leaving systems vulnerable. Microsoft has stated that the "inetpub" folder should not be deleted and that its presence is part of security enhancements.

Winsage

April 24, 2025

Windows 11’s mysterious ‘inetpub’ folder might be more dangerous than we thought

Windows 11 users have been warned about a potential vulnerability associated with the inetpub folder, introduced in the April 2025 security update. Security researcher Kevin Beaumont raised concerns that hackers could exploit this folder to disable essential security updates by creating "junction points" within the system's directory. This could lead to installation errors or force a rollback to previous system states due to a denial of service (DoS) vulnerability in the Windows servicing stack. Microsoft stated that the inetpub folder is part of a security patch (CVE-2025-21204) and advised against deleting it, claiming that removal would not impact system performance.

Winsage

April 24, 2025

Windows 11’s crucial new ‘inetpub’ folder is laughably easy to hack

A new folder named "inetpub" appeared on many Windows PCs after an April update, initially thought to be a glitch. Microsoft later stated that this folder was introduced to enhance Windows security by addressing the CVE-2025-21204 vulnerability. However, security researcher Kevin Beaumont revealed that the inetpub folder could allow attackers to bypass critical security updates. Beaumont proposed creating a junction point in the C: directory to prevent the inetpub folder's creation, which would also block the installation of the April update and subsequent security updates, leaving PCs vulnerable. This situation could lead to error messages and failed update rollbacks, with attackers able to exploit these issues without elevated privileges. Beaumont has informed Microsoft about the problem, but a response has not yet been received.

Winsage

April 22, 2025

Critical Windows Update Stack Vulnerability Allows Code Execution & Privilege Escalation

A security vulnerability identified as CVE-2025-21204 has been discovered in the Windows Update Stack, allowing local attackers to execute unauthorized code and escalate privileges to SYSTEM-level access. This vulnerability, with a CVSS score of 7.8 (High), affects Windows 10 versions 1507, 1607, and 1809, among likely other supported Windows 10/11 and Windows Server versions. The flaw arises from a design issue where Windows Update processes do not properly follow directory junctions, enabling attackers with limited user privileges to redirect trusted paths to locations containing malicious code. Microsoft has introduced a mitigation strategy in its April 2025 cumulative update, which includes creating a new folder at the root of system drives and implementing detection rules for suspicious junction creations. Organizations are advised to apply the April 2025 security updates, restrict ACLs on specific directories, prevent symbolic link creation, and monitor file creation activities in certain directories.