# This dangerous Windows Defender security flaw went unnoticed for 12 years, here's how to protect your PC today | Tech News (HT Tech) > In an ironic twist, the bug would allow an attacker to re-infect your PC after Microsoft Defender removed another virus, but there's an easy fix. # This dangerous Windows Defender security flaw went unnoticed for 12 years, here's how to protect your PC today ## In an ironic twist, the bug would allow an attacker to re-infect your PC after Microsoft Defender removed another virus, but there's an easy fix. Aug 21 2022, 15:02 IST ![Follow on Facebook](https://images.hindustantimes.com/tech/static/revamp/images/png/follow-us-facebook.png) ![Follow on Facebook](https://images.hindustantimes.com/tech/static/revamp/images/png/follow-us-facebook-hover.png) ![Share](https://images.hindustantimes.com/tech/static/revamp/images/png/Share.png) ![Share](https://images.hindustantimes.com/tech/static/revamp/images/png/Shareclicked.png) ![Share on WhatsApp](https://images.hindustantimes.com/tech/static/revamp/images/png/whatsapp.png) ![Share on WhatsApp](https://images.hindustantimes.com/tech/static/revamp/images/png/whatsapp-hover.png) ![Share on Twitter](https://images.hindustantimes.com/tech/static/revamp/images/png/twitter.png) ![Share on Twitter](https://images.hindustantimes.com/tech/static/revamp/images/png/twitter-hover.png) ![Share on Facebook](https://images.hindustantimes.com/tech/static/revamp/images/png/facebook.png) ![Share on Facebook](https://images.hindustantimes.com/tech/static/revamp/images/png/facebook-hover.png) ![Bookmark](https://images.hindustantimes.com/tech/static/revamp/images/png/Bookmark.png) ![Bookmarked](https://images.hindustantimes.com/tech/static/revamp/images/png/Bookmarked.png) ![When Microsoft Defender identifies a piece of malware, it usually puts a harmless one in its place while the clean up occurs.](https://images.hindustantimes.com/tech/img/2021/02/14/1600x900/_9127974a-54a2-11ea-a3cd-8211a7b3c8e4_1613289836276.jpg) When Microsoft Defender identifies a piece of malware, it usually puts a harmless one in its place while the clean up occurs. (Microsoft) ![Author Photo](https://images.hindustantimes.com/tech/static/revamp/images/png/HTTech-new-circle-logo.png) ### By HT TECH Microsoft Defender is one of the most reliable antivirus solutions available today if you use a PC with Windows 10, but that doesn’t mean that the software is without flaws. The company recently patched a serious bug in its software that was completely undetected for 12 years, according to a new report. When Microsoft Defender identifies a piece of malware, it usually puts a harmless one in its place while the clean up occurs. This is presumably to stop any programs from crashing. The security vulnerability was discovered by a security firm called SentinelOne, which found that the bug was located in a driver file the antivirus uses to get rid of malware installed on the PC, according to a report from Ars Technica. Also read: Microsoft to remove Edge Legacy desktop app with April’s Windows 10 Tuesday release Also read click here. The bug stems from the method in which that file is replaced - Windows Defender didn’t check whether the file it placed there was the right one, leaving the door wide open for misuse by another software to manipulate what file was placed. Once in, an attacker could use regular software that runs on a lower level (like a notepad service) to simply bypass all the administrator blocks set in place by Windows and edit the filesystem at a system level. It is sort of ironic that an antivirus program might end up being the tool used to reinfect a PC after cleaning up one virus. Microsoft has fixed the bug, thankfully, because the software ships with every Windows computer by default. Every single PC that was not protected by some other antivirus would thus be vulnerable to being exploited. SentinelOne reported the issue in November and the company then worked on a fix for the bug. Read more: Microsoft teams up with chipmakers to boost PC security According to the report, however, not everyone can access the vulnerability to exploit it. An attacker would still need remote or local access to the computer they wanted to target and they would still need to compromise the Windows PC first. Nevertheless, it is good that Windows has patched the issue already - the company says that anyone who has already updated to the February 9 patch update is already protected. If you haven’t yet, now would be a good time to hit the update button, or better still, enable automatic updates instead. Catch all the Latest Tech News, Mobile News, Laptop News, Gaming news, Wearables News , How To News, also keep up with us on Whatsapp channel,Twitter, Facebook, Google News, and Instagram. For our latest videos, subscribe to our YouTube channel. 14 Feb, 13:52 IST microsoft windows 10 ![HT Tech Awards](https://tech.hindustantimes.com/ht-tech-power-list-awards-2026/httech-awards-banner-new.webp) ### Related Stories 29 Sept 2026 71,613,286,835,190 NEXT ARTICLE BEGINS ![View all](https://images.hindustantimes.com/tech/static/revamp/images/png/view-all-icon.png) ## Tips & Tricks ![Ghibli-style art](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### How to turn your photos into Ghibli-style art with ChatGPT for free: Step-by-step guide ![How to create an invitation using iPhone’s new Apple Invites app- Step-by-step guide](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### How to create an invitation using iPhone’s new Apple Invites app- Step-by-step guide ![Apple TV app arrives on Android phones and tablets: What you get and how to install it](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Apple TV app arrives on Android phones and tablets: What you get and how to install it ![Vodafone Idea OTT plans](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Vodafone Idea users can now stream 17 OTT apps with one subscription: Here's how ![Android data transfer methods](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### How to transfer data from one Android to another using Google backup, USB-C cable, and more ## Editor’s Pick ![iPhone 16e launched with A18 chip, Apple AI—bringing flagship power on a budget: Check specs, price](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### iPhone 16e launched in India: All details about the new budget mobile from Apple ![DeepSeek was founded in China with only a fraction of the budget of the top AI companies in the US.](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### DeepSeek AI: How it works, who’s behind it, how it’s different from ChatGPT, and its big US market impact explained ![iPhone 17 Air likely to get this feature that iPhone 17 Pro models may miss out on](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### iPhone 17 Air likely to get this feature that iPhone 17 Pro models may miss out on ![Google Whisk AI explained: How remixing works, availability, and how it differs from Gemini](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Google Whisk AI explained: How remixing works, availability, and how it differs from Gemini ![iOS 18.4 beta arriving soon: Know why it is the biggest iPhone update](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### iOS 18.4 beta arriving soon: Know why it is the biggest iPhone update ## Trending Stories ![Airtel 5G SIM card will now be delivered in 10 minutes with Blinkit- How to order](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Airtel 5G SIM card will now be delivered in 10 minutes with Blinkit- How to order ![Infinix Note 50s 5G+](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Infinix Note 50s 5G+ set to launch in India with 64MP camera and MediaTek Dimensity 7300 SoC ![Xiaomi X Pro QLED Series sale starts in India: Check price, availability, and more](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Xiaomi X Pro QLED Series sale starts in India: Check price, availability, and more ![Apple Intelligence AI training](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Apple plans to train AI using your on-device data without accessing personal content or emails: Report ![CMF Buds 2](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### CMF Buds 2 key features and price revealed ahead of April 28 launch: Details inside keep up with tech ![Facebook](https://images.hindustantimes.com/tech/static/revamp/images/png/tech-facebook.png) ![Twitter](https://images.hindustantimes.com/tech/static/revamp/images/png/tech-twitter.png) ![WhatsApp](https://images.hindustantimes.com/tech/static/revamp/images/png/tech-whatsApp.png) ![Facebook](https://images.hindustantimes.com/tech/static/revamp/images/png/tech-facebook.png) ## Gaming ![Check out these five gaming monitors under ₹20,000,](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Top 5 gaming monitors under ₹20000 you should consider ![gaming consoles](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Grab gaming consoles at discounted rates during Amazon Great Indian Festival: Up to 72% off ![Pokémon GO Wild Area 2025](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Pokémon GO Wild Area 2025 to bring Grimmsnarl family, Shiny Hatenna, and global challenges ![Shade Silver](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Shade Silver free on Steam for a limited time: Here’s how to get it ![Call of duty](https://images.hindustantimes.com/tech/static/revamp/images/png/ht-tech-bg-img-90-66.png) ### Call of Duty: Black Ops 7 skips Switch 2 at launch, release date and price leak ![View all](https://images.hindustantimes.com/tech/static/revamp/images/png/view-all-icon.png) ## Trending News ### Airtel 5G SIM card will now be delivered in 10 minutes with Blinkit- How to order ![Airtel 5G SIM card will now be delivered in 10 minutes with Blinkit- How to order](https://images.livemint.com/static/static/1x1_img.gif) ### Infinix Note 50s 5G+ set to launch in India with 64MP camera and MediaTek Dimensity 7300 SoC ![Infinix Note 50s 5G+](https://images.livemint.com/static/static/1x1_img.gif) ### Xiaomi X Pro QLED Series sale starts in India: Check price, availability, and more ![Xiaomi X Pro QLED Series sale starts in India: Check price, availability, and more](https://images.livemint.com/static/static/1x1_img.gif) ### Apple plans to train AI using your on-device data without accessing personal content or emails: Report ![Apple Intelligence AI training](https://images.livemint.com/static/static/1x1_img.gif) ### CMF Buds 2 key features and price revealed ahead of April 28 launch: Details inside ![CMF Buds 2](https://images.livemint.com/static/static/1x1_img.gif) ## Trending Gadgets Mobiles Laptops Tablets ![HT Tech](https://images.hindustantimes.com/tech/static/revamp/images/png/HT_tech-new.gif) - https://tech.hindustantimes.com/tech/news/this-dangerous-windows-defender-security-flaw-went-unnoticed-for-12-years-71613286835190.html