
Imagine a wolf in sheep’s clothing – that’s FileFix. This insidious attack exploits a hidden weakness in how Windows and your web browser save webpages, turning a seemingly harmless function into a doorway for disaster. FileFix cleverly bypasses Windows’ security checks, opening the floodgates for ransomware, credential theft, and even the installation of entirely new malware strains. Is your PC vulnerable?
This guide unveils the protective measures you can implementright nowto fortify your defenses against the FileFix threat and keep your system secure. Don’t wait until it’s too late.
How FileFix Attack Works
A stealthy attack vector dubbed “FileFix” has been unearthed by security researcher mr.d0x, exploiting a loophole in how Windows trusts locally saved HTML files. The vulnerability lies in the “Save as” function. Saving a webpage bypasses the critical “Mark of the Web” (MoTW) security tag. This missing tag is a red flag for Windows Security, signaling it to scan the file for potential threats. Without it, danger slips right through the net.
Imagine a Trojan horse, but instead of soldiers, it carries malicious code hidden within a seemingly harmless HTML file. This file, with the innocent-looking extension “.hta,” bypasses Windows security checks and executes immediately when opened. A rogue website could trick you into saving this file and, crucially, renaming it with the “.hta” extension. Suddenly, you’ve unwittingly unleashed malware, executing malicious code as if it were a trusted application, all without Windows raising a single alarm. It’s a silent, stealthy attack that turns your own trust against you.
The real trick? Luring victims into saving the poisoned webpage as an HTML application. Think of it as a digital Trojan horse. Just like EDDIESTEALER, the key is masterful manipulation. Imagine convincing users, through carefully crafted scams, to safeguard their precious MFA codes under a file name ending in “.hta.” Boom. Access granted.
Thankfully, there are multiple points of interception to block this attack on your PC. Below are the most reliable ones.
Avoid Malicious Webpages
Imagine your computer as your home. A malicious webpage is like a shady character lurking outside. The best defense? Don’t open the door! Avoiding suspicious websites is your first line of defense against attacks like this one.
Next, fortify your digital fortress. Modern browsers like Chrome, Edge, and Firefox are equipped with builtin security systems to ward off phishing scams and malware. Think of them as your hightech security system.
For ultimate protection, consider Chrome’s “Enhanced Protection” mode. It’s like having an AI security guard constantly scanning for threats, offering realtime protection against the latest dangers. Stay vigilant, stay safe, and keep those digital doors locked!
Think twice before you click: Phishing emails are traps disguised as legitimate messages, leading you to malicious websites. Master the art of spotting these imposters, and avoid taking the bait. Accidentally stumbled onto a questionable site? Don’t panic. Learn the tell-tale signs that separate the real deal from a digital scam.
Make File Extensions Visible in Windows
Windows 11 plays hide-and-seek with your file extensions, concealing the true identity of your files. This seemingly harmless default setting? It’s FileFix’s secret weapon. Without visible extensions, a simple .html can morph into a dangerous .hta right under your nose. Don’t let your system be fooled! Expose those extensions and keep a vigilant eye on your file types. See everything, change nothing without your knowledge.
In File Explorer, click on theSee morebutton (three dots) and selectOptions.
Here, move to theViewtab and uncheck the optionHide extensions for known file types.

Now, you’ll always see file extensions even in the download window when saving the webpage.

Change .hta File Association to Notepad
Think of .HTA files as miniature web pages that run as desktop applications. Normally, they’re handled by Mshta, which smoothly executes their code. But, picture this: you accidentally tell your computer to open .HTA files with Notepad instead. Suddenly, those files become harmless walls of text. That potentially nasty .HTA file someone tricked you into downloading? Poof! It just sits there, unexecuted, because Notepad can’t run it – it can only display its insides. A simple file association change can turn a potential threat into a minor inconvenience.
Think .hta scripts are your concern? Probably not. These relics are usually confined to IT departments or powering dusty, old enterprise systems. Unless you’re actively relying on an .hta script, consider yourself safe from this change.
Tired of “.hta” files opening with the wrong program? Take control! Dive into Windows Settings, navigate toApps, thenDefault Apps. In the search bar under “Set a default for a file type or link type,” type “.hta” and reclaim your defaults!
Tired of .hta files launching into oblivion? Wrest control! Pinpoint “Microsoft (R) HTML Application host,” then banish the mystery by assigning Notepad as its rightful handler. Click “Set default” and watch as .hta files obediently unfurl within the familiar embrace of Notepad. Problem solved.

Disable Mshta to Block HTML Execution
Want to instantly neuter a dangerous Windows app? Here’s a ninja trick to completely disable MSHTA and prevent those pesky .hta scripts from running wild: rename “mshta.exe” to “mshta.exe.disabled”. Boom! Problem solved. Just make sure your file extensions are visible, or this cloak-and-dagger move won’t work.
Mshta file is in “C:\Windows\System32” and “C:\Windows\SysWOW64”, you need to disable it in both locations.
Silence the “mshta” menace! Think of “mshta.exe” as a sneaky back door in your Windows system. To slam it shut, you need to become a digital locksmith. First, venture into these hidden system folders using Windows Explorer. Once inside, unleash your inner keyboard ninja and type “mshta” – this will spotlight your target. Now, with administrator privileges, rename this rogue file to “mshta.exe.disabled,” effectively neutralizing it. You might need to wrestle control of the file ownership to accomplish this. Should you ever need to reopen this digital door, simply revert the names in both locations back to “mshta.exe.”

With this vulnerability exposed, Microsoft might rewrite the rules of engagement for MoTW in a future update. Keep your Windows defenses sharp and auto-updates enabled. Also, ensure that default Windows security protocols are active – they might just be the last line of defense against this script’s execution.
Thanks for reading New FileFix Attack Can Bypass Windows MoTW: How to Protect Your PC