If you’ve checked your C: drive recently and spotted a mysterious “inetpub” folder staring back, you’re not alone—and no, you didn’t accidentally sign up for IIS hosting in your sleep. Microsoft’s latest attempt at patching a high-profile security vulnerability has left IT pros and casual users alike scratching their heads, rolling their eyes, and, in the case of at least one intrepid security researcher, exploiting the “fix” to break Windows Updates wide open. Welcome to the world of defense-by-folder-creation, where the cure might just be more dangerous than the disease.
Let’s start with some context. Inetpub is, for many, a throwback: the default home for Internet Information Services (IIS) web server files on Windows servers. For anyone not running IIS, seeing this folder suddenly land on your system in 2025 is the digital equivalent of coming home to find a ghost has made you dinner—intriguing, but unsettling.
The catalyst for this surprise is CVE-2025-21204, a rather nasty privilege escalation vulnerability lurking in Windows Process Activation. The bug could have allowed a local attacker to gain system-level privileges using a symlink attack path—think of it as a crafty shortcut that lets a ne’er-do-well get somewhere they really shouldn’t.
But instead of patching the vulnerable code directly, Redmond simply pre-created the “c:\inetpub” folder by default. The rationale? If the folder already exists, attackers can’t replace it with a malicious symlink. In theory, it’s a decent fumble recovery: just block the attack by occupying the key real estate. In practice—well, let’s just say that’s where things start to fall apart.
Let’s have a frank moment, IT admins: nothing sets off warning sirens like mystery folders appearing—especially ones that harken back to the turn-of-the-century Microsoft. You can almost hear the XP startup sound echoing in your mind.
However, there’s something uniquely 1995 about this whack-a-mole approach. This time, the patch was more “spackle and hope” than substantive fix—the only thing more ephemeral than the bug itself was the sense of assurance among sysadmins. The “inetpub” workaround does exactly one thing: makes sure the folder exists. No additional mechanisms, no hardened permissions, nothing to stop creative mischief.
Sysadmins know the pattern: “temporary” workarounds tend to linger, slowly fossilizing into “expected behavior.” At least until an enterprising researcher finds a way to turn that band-aid into a fresh wound.
Let’s break it down. The mklink command is a Windows PowerShell and Command Prompt staple—a tool for creating symbolic and hard links across your file system. Used properly, it’s a workhorse. Used creatively? Well, let’s just say things get interesting.
Beaumont discovered that by running:
mklink /j c:\inetpub c:\windows\system32\notepad.exe
…he could turn c:\inetpub into a junction pointing directly to Notepad’s executable. Now, when Windows Update came along, looking to interact with inetpub, it found itself staring, blankly (presumably as blankly as Notepad itself) at the wrong file. Error. Rollback. No updates.
The punchline? No administrator rights required on most default systems. Standard users—those delightfully nontechnical individuals you spent all last week onboarding to Teams—can trigger the same trick. That’s right: your accounts payable intern just became an accidental threat actor.
Let’s pause for a moment to appreciate the sheer elegance (and horror) of this hack. It’s so simple, so predictable, and yet so devastating. At this point, you’d almost think Redmond was running a contest to see who could break Windows Updates with the least amount of code.
The trouble is, mitigations that only consider the folder’s existence miss the broader attack surface. Unless proper permissions and locking mechanisms are enforced, folders like inetpub become sitting ducks for junction attacks.
Microsoft, to its credit (again, briefly), is hardly the only culprit here. Many a vendor has fallen afoul of the forgotten folder, the lazy symlink, or the quietly subverted update process. But when you’re the steward of 1.5 billion Windows installations, the margin for error is a tad slimmer.
First, your notifications about critical Windows updates—always shifting between “urgent” and “catastrophic”—now need a third category: “broken due to a workaround.” Any enterprising user with Cmd.exe and a bit of attitude can bork their update mechanism, intentionally or otherwise.
From a support perspective, it means quicker escalations, longer troubleshooting sessions, and more frustrated users (and managers). Imagine a monthly patch cycle when a third of your endpoints refuse to update, and all roads trace back to a misbehaving inetpub junction. Good luck explaining that to an auditor.
From a security perspective, the risk is twofold: endpoints locked into old, vulnerable states, and forensic headaches when trying to trace why a critical patch failed to deploy. For organizations under compliance mandates, the mere appearance of “bogus” system folders can create additional work (and worries) during audits.
Of course, we haven’t even touched on the psychological toll—having to explain, repeatedly, that yes, a folder named after the world’s least-loved web server really is causing your security patch to fail in 2025.
For now, organizations are left to roll their own mitigations. This likely means scanning endpoints for suspicious junctions, scripting repairs, and doing damage control for any business units caught in the crossfire. All while hoping the next official fix doesn’t open another can of worms.
It’s worth highlighting the real-world implications: security “workarounds” unevaluated beyond lab scenarios can (and do) become new vectors for disruption. Theoretical attacks quickly become copy-paste fodder across security blogs and underground forums.
In the meantime, should you spot inetpub on your C: drive where previously it was naught but empty space, take it as a gentle reminder that even the best-laid plans of Microsoft and admins often go off the rails—sometimes, spectacularly so.
This incident also underscores a larger trend: the accelerating arms race between attackers, defenders, and the hopes and dreams of everyday users just trying to get their work done. Every quick fix has the potential to become the next headline—not to mention the next audit finding.
If there’s humor to be found (and there always is), it’s perhaps in the sheer predictability of it all. Windows updates break things. Security mitigations break more. And in the end, everyone just wants a stable, secure desktop where folders appear for actual reasons—ideally, not as relics of IIS installations past.
Microsoft will issue a fix for the fix. Another creative soul will break it in turn. The cycle continues, as it has since the days of Windows 95—and possibly until some future where folders and symlinks are a quaint memory, like dial-up modems or the Clippy Office Assistant.
So, dear reader, check your folders, brace for impact, and prepare once again for the unending saga of Windows updates. If nothing else, your C: drive will never be short of surprises.
And if you find yourself inexplicably yearning for an IIS folder in 2025…well, consider yourself part of Windows history—right there in the front row, watching Redmond attempt to patch the patch, with all the grace of a Jenga tower on a rickety desk.
Here’s to the next round—may your updates run smoothly, your folders remain unremarkable, and your mklink usage stay confined to the righteous and the true.
Source: theregister.com Microsoft mystery folder fix might need a fix of its own
The Ghosts of IIS Past: Why Is There an inetpub Folder on My Machine?
Let’s start with some context. Inetpub is, for many, a throwback: the default home for Internet Information Services (IIS) web server files on Windows servers. For anyone not running IIS, seeing this folder suddenly land on your system in 2025 is the digital equivalent of coming home to find a ghost has made you dinner—intriguing, but unsettling.The catalyst for this surprise is CVE-2025-21204, a rather nasty privilege escalation vulnerability lurking in Windows Process Activation. The bug could have allowed a local attacker to gain system-level privileges using a symlink attack path—think of it as a crafty shortcut that lets a ne’er-do-well get somewhere they really shouldn’t.
But instead of patching the vulnerable code directly, Redmond simply pre-created the “c:\inetpub” folder by default. The rationale? If the folder already exists, attackers can’t replace it with a malicious symlink. In theory, it’s a decent fumble recovery: just block the attack by occupying the key real estate. In practice—well, let’s just say that’s where things start to fall apart.
Let’s have a frank moment, IT admins: nothing sets off warning sirens like mystery folders appearing—especially ones that harken back to the turn-of-the-century Microsoft. You can almost hear the XP startup sound echoing in your mind.
Patch and Pray: Microsoft’s Folder-First Security Mitigation
In Microsoft’s defense (though this will be brief, I promise), pre-creating potentially exploitable folders isn’t new, especially under time pressure. And with symlink/junction-based attacks popping up like mushrooms after rain, shortcuts (pun intended) are tempting.However, there’s something uniquely 1995 about this whack-a-mole approach. This time, the patch was more “spackle and hope” than substantive fix—the only thing more ephemeral than the bug itself was the sense of assurance among sysadmins. The “inetpub” workaround does exactly one thing: makes sure the folder exists. No additional mechanisms, no hardened permissions, nothing to stop creative mischief.
Sysadmins know the pattern: “temporary” workarounds tend to linger, slowly fossilizing into “expected behavior.” At least until an enterprising researcher finds a way to turn that band-aid into a fresh wound.
Researcher in the Machine: How mklink Turns the Fix Against Itself
Enter Kevin Beaumont, whose unique blend of curiosity, technical prowess, and perhaps a smidgeon of mischief, led him to turn Microsoft’s fix into a DIY denial-of-service attack path.Let’s break it down. The mklink command is a Windows PowerShell and Command Prompt staple—a tool for creating symbolic and hard links across your file system. Used properly, it’s a workhorse. Used creatively? Well, let’s just say things get interesting.
Beaumont discovered that by running:
mklink /j c:\inetpub c:\windows\system32\notepad.exe
…he could turn c:\inetpub into a junction pointing directly to Notepad’s executable. Now, when Windows Update came along, looking to interact with inetpub, it found itself staring, blankly (presumably as blankly as Notepad itself) at the wrong file. Error. Rollback. No updates.
The punchline? No administrator rights required on most default systems. Standard users—those delightfully nontechnical individuals you spent all last week onboarding to Teams—can trigger the same trick. That’s right: your accounts payable intern just became an accidental threat actor.
Let’s pause for a moment to appreciate the sheer elegance (and horror) of this hack. It’s so simple, so predictable, and yet so devastating. At this point, you’d almost think Redmond was running a contest to see who could break Windows Updates with the least amount of code.
File System Junctions: The Eternal Achilles Heel
Junctions and symlinks—those perennial favorites of pentesters and ransomware writers—have long haunted Windows developers and security teams. Their presence in modern OSes is a necessary evil, sometimes exploited by the bad guys, sometimes by administrators trying to keep their sanity amid an ocean of inconsistent folder structures.The trouble is, mitigations that only consider the folder’s existence miss the broader attack surface. Unless proper permissions and locking mechanisms are enforced, folders like inetpub become sitting ducks for junction attacks.
Microsoft, to its credit (again, briefly), is hardly the only culprit here. Many a vendor has fallen afoul of the forgotten folder, the lazy symlink, or the quietly subverted update process. But when you’re the steward of 1.5 billion Windows installations, the margin for error is a tad slimmer.
Windows Update as Collateral Damage: The Real Risk For IT Pros
So what does this mean for IT professionals and sysadmins pressed for time, patience, and spare hair follicles?First, your notifications about critical Windows updates—always shifting between “urgent” and “catastrophic”—now need a third category: “broken due to a workaround.” Any enterprising user with Cmd.exe and a bit of attitude can bork their update mechanism, intentionally or otherwise.
From a support perspective, it means quicker escalations, longer troubleshooting sessions, and more frustrated users (and managers). Imagine a monthly patch cycle when a third of your endpoints refuse to update, and all roads trace back to a misbehaving inetpub junction. Good luck explaining that to an auditor.
From a security perspective, the risk is twofold: endpoints locked into old, vulnerable states, and forensic headaches when trying to trace why a critical patch failed to deploy. For organizations under compliance mandates, the mere appearance of “bogus” system folders can create additional work (and worries) during audits.
Of course, we haven’t even touched on the psychological toll—having to explain, repeatedly, that yes, a folder named after the world’s least-loved web server really is causing your security patch to fail in 2025.
Microsoft’s Response: The Waiting Game (Again)
As of the initial report, Microsoft is aware of the issue. A fix is surely en route—eventually. But given this is hardly Redmond’s first folder-related rodeo, confidence is understandably low. The recurring pattern of “fix, break, patch again” wears thin on even the most forgiving IT staffers.For now, organizations are left to roll their own mitigations. This likely means scanning endpoints for suspicious junctions, scripting repairs, and doing damage control for any business units caught in the crossfire. All while hoping the next official fix doesn’t open another can of worms.
It’s worth highlighting the real-world implications: security “workarounds” unevaluated beyond lab scenarios can (and do) become new vectors for disruption. Theoretical attacks quickly become copy-paste fodder across security blogs and underground forums.
Lessons Learned (Maybe): What This Means for Windows Users and Admins
The takeaways from this affair are as predictable as they are wearying:- Workarounds are seldom substitutes for real fixes.
- Attackers (and well-intentioned researchers) will always probe for the weakest point.
- Windows Update remains an ever-present house of cards, prone to collapse from unexpected gusts of folder-based mischief.
In the meantime, should you spot inetpub on your C: drive where previously it was naught but empty space, take it as a gentle reminder that even the best-laid plans of Microsoft and admins often go off the rails—sometimes, spectacularly so.
The Broader Security Picture: Layered Defense or Patchwork Quilt?
Security is, at its best, a layered strategy—where isolated missteps don’t cascade into disaster. Unfortunately, folder-first mitigations are about as robust as putting a sticky note over a broken lock. Determined attackers (or savvy interns) will find a way through.This incident also underscores a larger trend: the accelerating arms race between attackers, defenders, and the hopes and dreams of everyday users just trying to get their work done. Every quick fix has the potential to become the next headline—not to mention the next audit finding.
If there’s humor to be found (and there always is), it’s perhaps in the sheer predictability of it all. Windows updates break things. Security mitigations break more. And in the end, everyone just wants a stable, secure desktop where folders appear for actual reasons—ideally, not as relics of IIS installations past.
Awaiting the Next Adventure: The Eternal Sysadmin Cycle
Ultimately, this story is equal parts cautionary tale and relatable IT comedy. For every folder that pops into existence to block one vulnerability, a pathway is paved for the next would-be attacker (or, let’s face it, bored office prankster).Microsoft will issue a fix for the fix. Another creative soul will break it in turn. The cycle continues, as it has since the days of Windows 95—and possibly until some future where folders and symlinks are a quaint memory, like dial-up modems or the Clippy Office Assistant.
So, dear reader, check your folders, brace for impact, and prepare once again for the unending saga of Windows updates. If nothing else, your C: drive will never be short of surprises.
And if you find yourself inexplicably yearning for an IIS folder in 2025…well, consider yourself part of Windows history—right there in the front row, watching Redmond attempt to patch the patch, with all the grace of a Jenga tower on a rickety desk.
Here’s to the next round—may your updates run smoothly, your folders remain unremarkable, and your mklink usage stay confined to the righteous and the true.
Source: theregister.com Microsoft mystery folder fix might need a fix of its own
