Malicious extensions and ClickFix attacks are two hugely popular topics on our blog, and for a good reason: they’re both very common. In this post, we bring them together. Here’s the thing: in our posts about malicious ClickFix instructions, we don’t always explain exactly how users end up on the attackers’ pages in the first place. A recent study gives us a chance to fill that gap and talk about one of those methods: malicious extensions.

Readers who are not deep into cybersecurity may already have a bunch of questions at this point: how can extensions be malicious? where do they come from? and what exactly is ClickFix, anyway? Fret not: this post answers all these questions.

The danger of browser extensions

Let’s start with the basics. Browser extensions or add-ons are lightweight tools installed in your browser to give it extra capabilities or change how it works with web pages. For example, extensions can block ads, translate pages, download audio and video, save passwords, or take screenshots.

Most browser developers offer users an official extension store. For instance, for the most popular browser, Chrome, that store is the Chrome Web Store. There are also alternative platforms for distributing extensions, though browser developers have recently made it much harder to install and use extensions that don’t come from an official source.

Just like any other software, extensions can be useful, but they can also be malicious. In fact, cybercriminals often spread malicious extensions through those very same official stores, and we’ve covered plenty of such cases on our blog before.

It’s no accident that criminals love spreading malicious plug-ins. To work properly, most extensions need permission to read and modify the content of every web page the user visits. Without that permission, add-ons would be basically useless. For instance, a translation extension needs to read all the text on a page before it can swap the original for the translation.

Cybercriminals take advantage of these capabilities for their own purposes: for example, they intercept logins, passwords and other data entered on websites, swap out payment details, or show victims fake forms and messages. And all of this happens on legitimate sites that users have come to trust without a second thought.

Now let’s move on to a fresh piece of research about a campaign that spread 19 malicious add-ons through the Chrome and Edge extension stores. We’ll use it as an example to look at what these tools can actually do.

Almost twenty malicious extensions for Chrome and Edge

In late August, cybersecurity researchers reported finding 18 malicious extensions for Chrome and one for Edge. They said all 19 add-ons were probably linked to the same campaign. They base this on the similarity of the malicious code and the methods the attackers used. You’ll find the full list of malicious extensions at the end of this post.

Most of the extensions discovered, 14 in total, were built by the attackers themselves. Their first versions weren’t malicious at all and did exactly what users downloaded them for. But after a while, once users had come to trust the add-on, the attackers pushed an update that slipped in malicious functionality.

As for the remaining five extensions, their creators had nothing to do with the cybercriminals at all. They simply sold their creations to them. This way of getting hold of extensions is also popular among cybercrooks. There are plenty of reasons for that: ready-made add-ons can be bought for relatively little money, and criminals don’t have to build or promote them from scratch. And most importantly, along with the extension, they also inherit its existing user base. Upon buying the add-on, all the attackers need to do is add malicious functions and push an update that installs automatically for users. Users are never told that the extension’s real owner has changed.

In this case, the add-on cybercriminals bought most often was Enable Right Click & Copy — Smart Unlock + OCR. It had 70 000 users in Chrome and 10 000 in Edge. This purchase is exactly why there’s a single Edge extension among all its Chrome relatives. The add-on itself originally served a perfectly benign purpose: it let users select and copy text on sites where that’s normally blocked, and it could also pull text out of images with optical character recognition (OCR).

The malicious functionality introduced into the extension makes it reach out to the attackers’ command-and-control (C2) server to download additional modules of nefarious code. These modules can change over time. Since Chrome automatically updates all installed extensions by default, the malicious version lands on the device without users having to do anything at all.

For the downloaded code to run on the websites the user visits, the extension disables one of their defenses — Content Security Policy (CSP). This mechanism allows website owners to declare which scripts and other resources are allowed to load and run on a page. Once this protection is turned off, the extension can inject code it gets from the C2 server right into the pages open in the browser. The website itself isn’t hacked, and it looks the same to everyone else, but for that one infected user, the legitimate page quietly turns malicious.

What these 19 extensions can do

Now let’s take a closer look at what the malicious modules loaded by the extension are actually capable of. Researchers found 16 such modules, built for all sorts of tasks: from stealing data and hijacking cryptocurrency to the ClickFix attacks we’re focusing on here.

Some of the modules simply collect user data. They intercept logins, passwords, email addresses, and other valuable information the user enters into web forms, including payment details. On top of that, the add-ons steal data from Facebook and LinkedIn accounts and collect browsing history. Criminals can use this information to take over accounts, steal money, and launch further attacks against the victim.

A few other modules focus specifically on stealing cryptocurrency and related data directly. One of them is a crypto drainer, a tool that empties crypto wallets. It works with Ethereum and compatible blockchains as well as Solana and Tron. It replaces the real Connect Wallet and Swap buttons on websites with its own fake ones. When a user clicks one of these buttons, the drainer takes over all further interaction with the wallet and walks the victim through confirming the actions needed to steal their cryptocurrency.

Other modules target users of Ledger and Trezor hardware wallets. Right on the official websites of these services, the malicious extension displays a fake wallet update-and-restore page that asks for a seed phrase of 12, 18, or 24 words. The seed phrase the user enters is forwarded straight to the attackers, giving them full control over the wallet.

Finally, some modules gather information from crypto service pages open in the browser, such as OKX, MEXC, Kraken, KuCoin, Coinbase, Binance, Bybit, and MetaMask, including balance details and active session data that can be used to hijack accounts.

And now we’ve finally reached the module that matters most for this post: the one used for ClickFix attacks. We’ll talk about it in the next part.

How malicious extensions are used in ClickFix attacks

The ClickFix attack technique has become extremely popular among cybercriminals lately. It relies on social engineering: the victim is shown fake instructions supposedly needed to complete some action, such as passing a CAPTCHA check, fixing an error, or updating a program. Following these instructions, the user copies the command suggested by the attackers, pastes it into a system tool built for running these commands, and runs it, all by themselves.

We’ve written about attacks like this and their consequences more than once on our blog. But we rarely dig into exactly how a victim ends up on a page with fake instructions in the first place. A campaign that spread malicious extensions through the Chrome Web Store shows us one way this can happen.

Add-ons turn out to be a very handy tool for ClickFix attacks. As we mentioned earlier, when a user visits a page, extensions are allowed reading and changing its content in order to work. That gives attackers the chance to swap in a fake ClickFix instruction at just the right moment, replacing the content of the page the person actually wanted to open.

What’s more, the ClickFix technique itself lets attackers break out of the browser and gain a foothold directly in the system. That means removing the malicious extension won’t necessarily undo the damage: after the user has run the ClickFix command, malware may already be installed outside the browser.

In the specific attack example the researchers describe, the user sees a fake notification saying their browser needs to be updated, along with instructions on how to do it. The instructions change depending on the operating system, and the extension picks up that information automatically too.

How to avoid falling victim to infected extensions

First off, we recommend checking whether any of the following malicious extensions are already installed in your browser:

• Enable Right Click & Copy — Smart Unlock + OCR
• RapidLens – Google Lens for Screen Search & Images
• QuickLens – Search Screen with Google Lens
• Password Protect PDF
• Allow Copy – Select & Enable Right Click
• PixelCheck
• Creative Library – Ad Spy Tool
• Website Traffic Checker: MirrorSphere SEO Stats
• Site Signal – Website Traffic & SEO Checker
• SEO Pulse Pro – Website Traffic & SEO Analyzer
• Private Crypto News Reader
• Blockfolio: Address Monitor
• Crypto Rates & Fiat Converter
• Crypto Alerter: Price Alarms & Volatility Warnings
• DeFi Pulse Tracker
• Crypto Price Badge: Quick Glance
• Multi-Chain Explorer
• LedgerLook: Wallet Checker
• Meta & Facebook Ad Library Spy — Save Ads, Finder, Downloader | FeedX-Ray

If you find any of these extensions on your device, we recommend removing it as soon as you can and running a full system scan with a reliable antivirus. As we mentioned above, simply deleting the add-on might not be enough. You can use a free trial version to detect and remove the infection.

How to avoid falling victim to malicious extensions and ClickFix attacks in the future?

• Don’t install too many extensions and regularly check the list of those you have.
• Remove extensions you don’t use.
• Trust the warnings from your operating system and security software, rather than the instructions — or even the demands — of websites and apps.
• Install a trusted security solution on all your devices.

What else makes browser extensions and the ClickFix technique dangerous? Find out in our other posts:

• Bad advice for gamers: ClickFix hits Steam forums
• ClickFix on macOS: how Apple users are being scammed
• Infostealer has entered the chat
• AI sidebar spoofing: a new attack on AI browsers
• Dangerous browser extensions

In 2026, the owner of an ordinary home router, smart TV, or TV box is a prime target for cybercriminals. These devices are readily recruited into botnets and residential proxy networks, which we’ve covered before.

Criminals “sublease” the infected device by letting outsiders pay to visit any website from the victim’s IP address, so it looks like the device’s owner is doing it. The service is in demand across all kinds of shady schemes: from ad fraud and spam campaigns to password bruteforcing and account hacking. In our previous post, we described how home routers get recruited into these proxy networks; today we take a look at an even more vulnerable, and equally ubiquitous category of devices: smart TVs and TV boxes.

These appeal to criminals for two reasons. First, unlike computers and smartphones, TVs are almost always plugged into the power and have a fast internet connection. A dark screen doesn’t mean the device is switched off. On top of that, the limited user interface and monitoring tools mean suspicious background processes can easily slip unnoticed past users.

The threat is evolving and growing more aggressive. A recent study found that once proxyware turns up on a set-top box, the risks to its owner go well beyond having their traffic siphoned off.

Anatomy of the infection

The researchers focused on a popular TV box by SuperBox, which we already covered earlier in the post Is your TV box renting out your network?

SuperBox’s marketing leans heavily on the promise of providing thousands of TV channels, with no subscription or monthly fees. But out of the box, the device can’t actually do anything of the sort. To get access to pirated content, you need to install the brand’s proprietary app store.

When you launch it and install additional apps, the thousands of TV channels do appear. Meanwhile behind the scenes, with no warnings or permission prompts, the device floods external sites with unauthorized requests, and network traffic spikes sharply.

The researchers uncovered several alarming facts. First, the victim gets enrolled into as many as five botnets at once. The SuperBox runs clients for several proxyware networks simultaneously, which even try to compete with one another by blocking rival software from being installed.

But the real shock was the attacks on the internal network. The TV box’s proxyware places no limits on what its paying clients can actually do on the network. They can reach not only external sites but also devices inside your home network.

Normally, your home router and ISP settings protect you from outside attacks. But proxyware bypasses these barriers because it operates from inside the network. During an experiment, the researchers confirmed that an attacker on the internet can easily leverage the infected set-top box to open the admin panel of a home router, such as a Linksys, which is supposed to be accessible only to its owner when connected to the home Wi-Fi network. This means hackers can try to steal data from other devices in the same household, or even encrypt home network storage (NAS).

At the same time, flaws in SuperBox’s factory firmware let hackers remotely install and run any application with superuser privileges, and the threat is anything but hypothetical. Over three weeks of monitoring, the test set-top box was hit by more than 1300 attacks through the home proxy network. Attackers installed three different types of malware, including a module for launching DDoS attacks.

The malware uses several methods to gain a foothold in the system, and it survives reboots and power failures alike.

How to tell if your set-top box is working for hackers

If you have a cheap TV set-top box or Android TV from a little-known brand, it’s worth checking it for anomalies.

The most reliable method is to review the network traffic. Use the statistics in your router’s control panel, but note that some budget models may lack this feature. This feature is called Traffic Analyzer on Asus routers, Traffic Usage on TP-Link, and Traffic Monitor on Keenetic. Find your TV or set-top box in the device list and check the ratio of downloaded to uploaded data. They should consume a lot of traffic to download video while sending very little. If your box is quietly pushing gigabytes of data out or staying chatty on the network even while idle, that’s a telltale sign it’s infected.

If traffic statistics aren’t available, look for indirect signs:

• The network and memory activity LEDs won’t stop blinking even though no one’s using the device.
• The set-top box’s casing is constantly warm or hot.
• The interface lags behind the remote, and the box freezes at random moments that have nothing to do with heavy video playback.
• Your other devices (computers or phones) are seeing a real drop in internet speed.
• When trying to visit familiar sites over your home Wi-Fi, you’re constantly hit with a CAPTCHA — a sign your network may be compromised and flagged as a spam source.
• Your ISP’s tech support calls you asking about suspicious network loads.

What to do with an infected device

The best solution is to disconnect the device from the internet and dispose of it. If you have to keep using it, follow these steps to minimize the risks:

1. Do a factory (hard) reset. Restore the set-top box to its original state.
2. Take it offline before setting up again. The first time you turn it on after a reset, skip the Wi-Fi setup step and don’t plug in the Ethernet cable.
3. Block app installation. Go to Android settings and disable installation of apps from unknown sources. Be sure to turn off any debugging features if enabled: USB debugging, Wireless debugging, and ADB. Menu item names may differ depending on your Android version and device manufacturer.
4. Isolate it on the network. Set up a guest Wi-Fi network on your router and connect the TV box to it. Enable Client Isolation in your router’s settings, if it has it. This will stop the box from seeing other devices on your home network, which protects your computers and network storage.
5. Check for updates. Once the box is connected to the guest network, check for official firmware updates: manufacturers sometimes patch known vulnerabilities, though with lesser-known brands, you shouldn’t count on it.

Your most reliable safeguards

Buying cheap devices with pirate streaming features and installing software from shady sources is a surefire way to compromise your home network. Your IP address will become a source of malicious activity, which at best gets you blocked by your ISP and at worst puts you on law enforcement’s radar. What’s more, hackers can use the box as a launchpad to attack your home computers and NAS, which can lead to personal data theft or a ransomware attack.

The best protection is to buy devices from trusted brands and pay for legal content. And to rule out someone hijacking control of your network, make sure your router’s admin panel and other home devices are protected with unique, strong passwords. To avoid having to remember them all, use a reliable password manager such as Kaspersky Password Manager. Additionally, the Smart Home Monitor feature included in Kaspersky Premium lets you keep all your devices fully under control.

There may be more things you don’t know about your smart home devices:

• Is your TV box renting out your network?
• Are your TV, smartphone, and smart speakers eavesdropping on you?
• Five rules to stop IP cameras from spying on you
• The hidden risks of cheap Android devices
• Is your router secretly working for foreign intelligence?

BlueMoon, a shared Chrome and Windows exploit kit, shows why “patch later” is becoming a dangerous gamble.

Security updates are easy to put off. The browser still opens, Windows still works, and choosing to relaunch your browser or restart your computer later can feel harmless.

But a newly documented exploit kit called “BlueMoon” shows how quickly patching delays can become dangerous. Proofpoint Researchers found four espionage groups using the same exploit chain against Chrome browsers running on Windows within days of one another.

The campaign is a timely reminder that once a security flaw, or even its fix, becomes public, attackers may move faster than many users expect.

The attacks began with phishing emails. A victim who clicked a malicious link could be sent to a web page designed to exploit two vulnerabilities in Chrome’s V8 JavaScript engine, followed by a Windows vulnerability to break out of the browser’s protections and gain higher privileges on the computer.

The Chrome vulnerabilities used by BlueMoon were patched in the Stable channel on September 3 and September 8, 2026. The first was already actively exploited when Google released its update. Microsoft addressed the Windows vulnerability in its September Patch Tuesday updates, by which point it was also being exploited.

CISA has since added all three flaws to its Known Exploited Vulnerabilities (KEV) catalog, which lists vulnerabilities known to have been exploited in real-world attacks.

The notable part is not just that BlueMoon exploited the flaws, but how quickly the capability appears to have spread. Publicly visible upstream fixes can give attackers clues before downstream browser updates reach users, allowing a weaponized chain to be developed and adopted by multiple groups very quickly.

Does that mean that patches can no longer be tested before they are released to the public? No, but we may need to rethink how they are tested and deployed, because it appears some cybercriminals are effectively beta-testing the patches themselves.

The researchers also found clues, but no conclusive evidence, that the exploit kit was developed with AI assistance. The broader concern is credible: AI tools can help attackers interpret source-code changes, write and modify code, document test results, and learn from failed attempts.

In practical terms, the gap between “a flaw is fixed upstream” and “most people are protected” may be increasingly valuable to attackers. We should try to minimize that gap.

How to stay safe

Not every security update needs to be installed the moment it appears. In organizations especially, updates may need testing, staged deployment, and contingency plans. But vulnerabilities known to be actively exploited deserve greater priority. That is precisely why CISA’s KEV catalog is so important: It helps organizations identify the vulnerabilities they should address first.

For home users:

• Install browser and operating-system updates promptly. Use the few minutes they take to grab a drink rather than repeatedly postponing them.
• Don’t click links in unsolicited emails.
• Use up-to-date, real-time anti-malware protection to help catch the malware that exploit kits attempt to deliver.

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Stop threats before they can do any harm.

Malwarebytes Browser Guard blocks phishing pages and malicious sites automatically. Free, one click to install. Add it to your browser →

BlueMoon, a shared Chrome and Windows exploit kit, shows why “patch later” is becoming a dangerous gamble.

Security updates are easy to put off. The browser still opens, Windows still works, and choosing to relaunch your browser or restart your computer later can feel harmless.

But a newly documented exploit kit called “BlueMoon” shows how quickly patching delays can become dangerous. Proofpoint Researchers found four espionage groups using the same exploit chain against Chrome browsers running on Windows within days of one another.

The campaign is a timely reminder that once a security flaw, or even its fix, becomes public, attackers may move faster than many users expect.

The attacks began with phishing emails. A victim who clicked a malicious link could be sent to a web page designed to exploit two vulnerabilities in Chrome’s V8 JavaScript engine, followed by a Windows vulnerability to break out of the browser’s protections and gain higher privileges on the computer.

The Chrome vulnerabilities used by BlueMoon were patched in the Stable channel on September 3 and September 8, 2026. The first was already actively exploited when Google released its update. Microsoft addressed the Windows vulnerability in its September Patch Tuesday updates, by which point it was also being exploited.

CISA has since added all three flaws to its Known Exploited Vulnerabilities (KEV) catalog, which lists vulnerabilities known to have been exploited in real-world attacks.

The notable part is not just that BlueMoon exploited the flaws, but how quickly the capability appears to have spread. Publicly visible upstream fixes can give attackers clues before downstream browser updates reach users, allowing a weaponized chain to be developed and adopted by multiple groups very quickly.

Does that mean that patches can no longer be tested before they are released to the public? No, but we may need to rethink how they are tested and deployed, because it appears some cybercriminals are effectively beta-testing the patches themselves.

The researchers also found clues, but no conclusive evidence, that the exploit kit was developed with AI assistance. The broader concern is credible: AI tools can help attackers interpret source-code changes, write and modify code, document test results, and learn from failed attempts.

In practical terms, the gap between “a flaw is fixed upstream” and “most people are protected” may be increasingly valuable to attackers. We should try to minimize that gap.

How to stay safe

Not every security update needs to be installed the moment it appears. In organizations especially, updates may need testing, staged deployment, and contingency plans. But vulnerabilities known to be actively exploited deserve greater priority. That is precisely why CISA’s KEV catalog is so important: It helps organizations identify the vulnerabilities they should address first.

For home users:

• Install browser and operating-system updates promptly. Use the few minutes they take to grab a drink rather than repeatedly postponing them.
• Don’t click links in unsolicited emails.
• Use up-to-date, real-time anti-malware protection to help catch the malware that exploit kits attempt to deliver.

---

Stop threats before they can do any harm.

Malwarebytes Browser Guard blocks phishing pages and malicious sites automatically. Free, one click to install. Add it to your browser →