Technology
Windows PCs at risk as new tool disarms built-in security
All modern Windows PCs come with Microsoft Defender built in. For the unaware, this tool is Windows’ native antivirus.
Over time, it has matured into a reliable security tool capable of blocking a wide range of threats. However, a tool called Defendnot can shut down Microsoft Defender completely, without exploiting a bug or using malware. It simply convinces Windows that another antivirus is already running.
The implications are serious. This tool does not break into the system or use advanced code injection. It uses Windows features the way they were designed to be used. And that makes the problem harder to detect and harder to fix.
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Windows software on a PC (Kurt “CyberGuy” Knutsson)
The tool works by pretending to be an antivirus
Windows is built to avoid running multiple antivirus products at once. When a third-party antivirus registers itself, Windows disables Microsoft Defender to prevent conflicts. Defendnot exploits this system using an undocumented API that security software uses to communicate with the Windows Security Center.
The tool registers a fake antivirus that appears legitimate to the system. It uses a dummy DLL and injects it into Task Manager, a trusted Windows process. By operating inside this signed process, Defendnot avoids signature checks and permission blocks. Once the fake antivirus is registered, Windows disables Microsoft Defender without warning or confirmation.
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No security alert is shown to the user. No visible changes are made to indicate that the system is unprotected. Unless someone checks manually, the machine remains open to attacks with no real-time protection running.
The tool also includes options to set a custom antivirus name, enable logging and configure automatic startup. It achieves persistence by creating a scheduled task that runs whenever the user logs in.
Windows software on a laptop (Kurt “CyberGuy” Knutsson)
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From GitHub takedown to a fresh build
Defendnot is based on an earlier project called No-Defender. That project used code from an actual antivirus product to fake registration. It gained attention quickly and was removed after a copyright complaint from the vendor whose code had been reused. The developer took the project down and walked away from it.
With Defendnot, the creator rebuilt the core features using original code. This version avoids copyright issues and uses a new method to achieve the same effect. It does not rely on another antivirus or third-party binaries. It was written from scratch to demonstrate how simple it is to manipulate Windows security from inside the system.
Microsoft Defender currently flags the tool as a threat. It detects and quarantines it under the name Win32/Sabsik.FL.!ml. However, the fact that it works at all points to a weakness in how Windows handles antivirus registration and trust.
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Windows laptop showing the home screen (Kurt “CyberGuy” Knutsson)
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6 ways to protect yourself from malicious programs
While Defendnot is a research project, there’s a chance that similar tools are already out there and could be used to compromise your PC. Here are a few tips to help you stay safe:
1. Use strong antivirus software: Even with regular updates, Windows systems can be left exposed by tools like Defendnot that silently disable built-in defenses. A strong third-party antivirus with real-time protection and frequent updates provides essential backup security. Look for solutions with real-time protection and frequent updates to tackle emerging threats. Get my picks for the best 2025 antivirus protection winners for your Windows, Mac, Android and iOS devices.
2. Limit exposure: Many exploits rely on user interaction, such as clicking a shady link, downloading a compromised file or mounting an untrusted virtual disk. Stick to reputable websites, avoid opening unsolicited email attachments and use a browser with built-in security features (like Microsoft Edge or Chrome with Safe Browsing enabled).
3. Avoid running unexpected commands: Never paste or run commands (like PowerShell scripts) you don’t understand or that were copied from random websites. Attackers often trick users into unknowingly running malware this way.
4. Keep your software updated: Regularly update your operating system, browsers and all software applications. Updates often include patches for security vulnerabilities that malware can exploit.
5. Use two-factor authentication (2FA): Enable 2FA on all your accounts. This adds an extra layer of security by requiring a second form of verification, making it harder for attackers to gain access even if they have your password.
6. Invest in personal data removal services: Even with strong device security, your personal information may still be exposed online through data brokers and people-finder sites. These services collect and publish details like your name, address and phone number, making you an easier target for identity theft or phishing. Automated data removal services track down these sites and submit removal requests on your behalf, helping to reduce your digital footprint and increase your online anonymity. While they can’t erase every trace of your information, they make it significantly harder for attackers to find and exploit your personal data, which saves you time and reduces unwanted spam in the process.
While no service promises to remove all your data from the internet, having a removal service is great if you want to constantly monitor and automate the process of removing your information from hundreds of sites continuously over a longer period of time. Check out my top picks for data removal services here.
Get a free scan to find out if your personal information is already out on the web.
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Kurt’s key takeaway
Defendnot points to a bigger issue with how Windows handles security. It takes a feature meant to prevent software conflicts and turns it into a way to completely disable protection. The system assumes any registered antivirus is legitimate, so if attackers can fake that, they get in without much resistance.
We often think of security as blocking the bad and trusting the good. But this case shows what happens when that trust is misplaced. Defendnot doesn’t sneak past Windows defenses. It walks right in using valid credentials. The solution isn’t just more patches or stronger malware signatures. What we need is a smarter way for systems to tell what is actually safe.
Do you think companies like Microsoft need to rethink how Windows handles antivirus registration and trust, given that tools like Defendnot can so easily disable built-in protections without using malware or exploiting a bug? Let us know by writing us at Cyberguy.com/Contact.
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Technology
SpaceX cuts a deal to maybe buy Cursor for $60 billion
SpaceX and Cursor are now working closely together to create the world’s best coding and knowledge work AI.
The combination of Cursor’s leading product and distribution to expert software engineers with SpaceX’s million H100 equivalent Colossus training supercomputer will allow us to build the world’s most useful models.
Cursor has also given SpaceX the right to acquire Cursor later this year for $60 billion or pay $10 billion for our work together.
Technology
Fake Windows update installs hidden malware
NEWYou can now listen to Fox News articles!
If you’ve ever clicked “Check for updates” and trusted what you saw, you’re not alone. That’s exactly what this latest scam is counting on.
The page mimics official branding, includes a believable knowledge base number and presents a big blue download button that feels familiar.
The catch? The download installs malware designed to steal passwords, payment details and account access.
According to researchers at Malwarebytes Labs, a cybersecurity research and threat intelligence team inside Malwarebytes, the site uses a typosquatted domain that looks close enough to a real Microsoft URL to fool a quick glance. That small trick is often all it takes.
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Cybersecurity researchers warn a fake Microsoft update site uses a look-alike URL and a familiar download button to deliver data-stealing malware. (Michael Nagle/Bloomberg via Getty Images)
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Why this fake Windows update malware slips past detection
At first glance, nothing seems off. The file looks like a standard Windows installer. It even lists “Microsoft” in its properties. That’s where this attack gets clever. Instead of using obvious malicious code, the attackers built the installer with legitimate tools and layered the attack in stages. Each piece looks harmless on its own.
Here’s what’s happening behind the scenes:
- The installer launches what appears to be a normal app
- That app quietly runs hidden scripts
- A disguised process loads a full Python environment
- Data theft tools activate in the background
Because each step looks routine, many security tools fail to flag it right away. Researchers also noted that antivirus engines initially showed zero detections for key parts of the attack. That does not mean the file is safe. It means the malicious behavior is well hidden.
What this fake Windows update malware is stealing
Once installed, the malware gets to work fast. It collects details about the infected device, including location and IP address. Then it reaches out to remote servers to receive instructions and upload stolen data.
The targets include:
- Saved browser passwords
- Login sessions and cookies
- Payment details
- Discord account tokens
It even tries to shut down other processes on your system to avoid interference while it works. In some cases, it modifies apps like Discord to intercept account activity in real time.
How the fake Windows update malware stays on your system
This malware is designed to stick around. It creates entries that look like normal system processes, so they blend in. One registry entry mimics Windows Security Health, which most users would ignore. It also drops a shortcut in your startup folder with a familiar name like Spotify. That makes it easy to overlook. Two different persistence tricks mean it can survive a reboot and keep running.
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A fake Windows update page is tricking users into downloading malware that steals passwords, payment details and account access. (Beata Zawrzel/NurPhoto)
Why this fake Windows update scam feels so real
There’s a bigger trend behind this. Researchers say campaigns like this often target regions where large data breaches have already exposed personal information. When attackers already know your name, provider or habits, they can build scams that feel tailored to you. That makes a fake Windows update page far more believable than a generic phishing email.
It also highlights something important. Today’s malware often hides inside legitimate tools and trusted frameworks. That makes it harder to detect and easier to trust. This campaign shows how far scammers have come. They are no longer relying on sloppy emails or obvious fake links. Instead, they are building layered attacks that look and behave like trusted software.
Even experienced users can get caught off guard when everything appears normal. The biggest takeaway is simple. A clean scan result or a familiar interface does not guarantee safety.
Microsoft says it’s aware of the threat
Microsoft confirmed it is tracking this type of activity and urges users to be cautious when downloading updates from unfamiliar sources.
“We are aware of reports of fraudulent websites impersonating Microsoft, and we actively work to detect and disrupt malicious activity across the internet,” A Microsoft spokesperson told CyberGuy. “We encourage customers to be cautious of unexpected prompts or downloads and to verify that they are interacting with legitimate Microsoft domains. As a best practice, we recommend users verify the legitimacy of a link by going directly to our website from your own saved favorite, from a web search, or by typing the domain name yourself.”
For more guidance on how to protect against online phishing scams, you can refer to Microsoft’s official support page at support.microsoft.com.
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A convincing Windows update scam is spreading malware that can grab saved passwords, cookies, payment data and Discord tokens. (Todor Tsvetkov/Getty Images)
Ways to stay safe from fake Windows update malware
You don’t need to be a security expert to avoid this. A few habits make a big difference.
1) Only update Windows from your settings
Go to Settings > Windows Update and check for updates there. Avoid downloading updates from websites.
2) Double-check the URL
Real Microsoft pages use microsoft.com. Anything else, even if it looks close, should raise a red flag.
3) Be cautious with urgent update prompts
If a site or message pressures you to install an update, stop and verify it manually.
4) Use strong antivirus software with behavior detection
Traditional antivirus software, which often comes built into your device or as basic security software, mainly looks for known threats using signature matching, which means it can miss new or well-hidden attacks like this one. Strong antivirus software uses behavior detection to monitor what programs are doing in real time, helping flag suspicious activity even if the malware hasn’t been seen before. Get my picks for the best 2026 antivirus protection winners for your Windows, Mac, Android & iOS devices at Cyberguy.com.
5) Use a data removal service to limit your exposure
If your personal information is already circulating online from past breaches, it can make scams like this more convincing. A data removal service helps reduce how much of your information is publicly available, making it harder for attackers to target you with tailored phishing attempts. Check out my top picks for data removal services and get a free scan to find out if your personal information is already out on the web by visiting Cyberguy.com
6) Turn on two-factor authentication
Two-factor authentication (2FA) adds a second layer of protection if your passwords are stolen.
7) Avoid downloading installer files from unknown sites
Legitimate updates rarely require manual downloads.
Kurt’s key takeaways
Fake updates are one of the most effective tricks because they tap into something we all trust. Keeping your system secure should not put you at risk, yet that’s exactly what attackers are exploiting here. The safest move is to slow down, verify where updates come from and stick to built-in tools whenever possible.
Are tech companies doing enough to keep fake updates from putting your data at risk? Let us know your thoughts in the comments below. Let us know by writing to us at Cyberguy.com.
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Copyright 2026 CyberGuy.com. All rights reserved.
Technology
The Vergecast Vergecast, 2026 edition
We get a lot of questions about how The Verge works. And how The Vergecast works. And how we make money. And whether some of that money helps Nilay buy more jackets, several yachts, or something else entirely. So, every once in a while, we spend an episode of the podcast answering as many questions as we can.
On this episode of The Vergecast, Nilay and David are joined by The Verge’s publisher, Helen Havlak, to talk about ads, subscriptions, our website, our audience, and more. Then, Nilay and David answer some more questions about how we think about journalism, our relationship with Verge alumni, video podcasts, and (of course) Brendan Carr.
Thanks to everyone who sent us questions for this episode, and please keep them coming! You can always call the Vergecast Hotline (866-VERGE11) or send us an email (vergecast@theverge.com) with your questions, thoughts, feelings, and misgivings about everything we’re up to. We truly love hearing from you. And if you want to be part of everything we’re up to, and help make The Verge even bigger and better, the best thing you can do is subscribe! You even get all our podcasts ad-free.
Oh, and also, in case you missed it yesterday, be sure and check out our emergency pod on the news that Tim Cook is stepping down as Apple CEO. We’ll be talking more about the future of Apple on Friday’s show, too, so send questions if you have ’em!
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