Understanding the Misconception About Extensions and Emails
Many users report a strange experience when opening emails from a particular domain: an extra extension appears to be added before the email is displayed. This has led to widespread confusion and even fear that their browser is being taken over without consent. However, after careful investigation, this premise is simply not supported by any legitimate technical behavior. No email domain, whether it is Domina or any other provider, has the ability to automatically install a browser extension or add one to the interface simply because you open an email. Extensions are programs that require explicit user action to install. They are not triggered by reading a message.
The confusion often arises from a combination of unrelated factors. Some users may have previously installed a browser add-on that modifies the Gmail or Outlook interface, such as a mail tracker or a theme changer. When they open an email, the extension's functionality runs, leading them to believe it was added at that moment. Others might encounter malicious scripts injected by fake extensions that they unknowingly installed through deceptive pop-ups or bundled software. These scripts can alter the appearance of the email reading pane, creating the illusion that a new feature has been added automatically. The key point is that none of this is caused by the email itself or the domain sending it. It is always a result of software already present on the user's machine.
Why Users Might Think an Extension Is Added Automatically
The rumor that opening an email adds an extension before the email might stem from a security campaign that came to light in early 2025. Researchers discovered a coordinated effort using 30 fake AI extensions to spy on Gmail users. These extensions were made available on the Chrome Web Store and disguised as helpful AI assistants. Once installed, they injected scripts directly into the Gmail page, allowing them to read email content and even capture microphone audio without the user's knowledge. The extensions did not install themselves automatically when an email was opened. Instead, victims had to manually add them, often tricked by deceptive advertisements or phishing messages. Nevertheless, the timing of the script injection sometimes caused a visual delay or a change in the Gmail interface that users misinterpreted as an extension appearing before the email loaded.
Another factor is the behavior of legitimate extensions like Mailtrack or Checker Plus for Gmail. These tools are installed deliberately by users who want extra features such as read receipts or inbox previews. When you open an email, the extension activates immediately, placing its icon or a new interface element next to or above the message. If you forget that you installed such an extension, you might think it was added by the email domain. In reality, it was already there, waiting to be triggered by the act of opening a message. This is a common source of the misconception.
How to Check for Unwanted Extensions in Your Browser
If you suspect that an extra extension is being added when you open emails, the first step is to inspect your browser's installed extensions. Follow these steps to see what is actually running:
- Open your browser (Chrome, Edge, Firefox, etc.) and go to the extensions or add-ons page. In Chrome, type chrome://extensions in the address bar.
- Look through the list of installed extensions. Check the toggle switch next to each one. If an extension you do not recognize is enabled, disable it by toggling it off.
- Click the Details button for any suspicious extension. Check the permissions it requests. If it requests access to all websites or to read your email, it could be malicious.
- Remove any extension that you did not install yourself or that you no longer trust. Use the Remove button to delete it completely.
- After cleaning up, restart your browser and open your email again. The extra element should no longer appear.
Performing this check regularly is a good security habit. Many users install hundreds of extensions over time and forget about them. Some of these may have been hijacked by updates or bundled with other software. Keeping your extension list lean and audited is one of the best ways to prevent unwanted behavior in your email interface.
Table: Legitimate vs Malicious Extensions Behavior
The table below compares how legitimate and malicious extensions act when you open an email. This will help you understand what is normal and what signals a potential threat.
| Feature | Legitimate Extension | Malicious Extension (Fake AI) |
|---|---|---|
| Installation method | User manually installs from official store after reading reviews | User is tricked into installing via phishing or deceptive ads |
| Behavior when email opens | Runs script that adds a visible feature like a tracking icon or a sidebar | Runs script that may silently read email content or alter the page without obvious visual change |
| Permissions | Requests minimal permissions, clearly stated (e.g., access to Gmail for a tracker) | Requests excessive permissions, like access to all websites or microphone |
| Ease of removal | Easily disabled or removed from extensions page | May hide removal buttons or reinstall itself |
| Intent | Provide a useful feature the user wants | Steal data, spy on activity, or inject ads |
Understanding these differences can help you quickly identify whether the extension you see is a helpful tool you installed earlier or a dangerous piece of malware that you need to eliminate.
How to Protect Yourself from Fake Extensions
Since the myth that an email domain automatically adds an extension is false, the real threat comes from extensions that users install voluntarily. To protect yourself, always follow these guidelines. First, only install extensions from trusted sources like the official Chrome Web Store or the extension marketplace for your browser. Even then, check the number of downloads, user ratings, and reviews. Be wary of extensions with very few downloads or that have been recently created. Many fake campaigns create new extensions every few days to evade detection. Second, avoid clicking on pop-ups or banners that claim your browser needs an update or that a new AI assistant is available for free. These are common lures for fake extensions. Third, read the permissions requested by any extension before installing it. If a simple email assistant asks for access to all your browsing data, that is a red flag.
Additionally, keep your browser and operating system up to date. Security patches often close vulnerabilities that fake extensions exploit. Use a reputable antivirus or anti-malware tool that can scan for potentially unwanted programs. Finally, if you notice unusual behavior in your email, such as missing messages, strange auto-replies, or interface changes that you cannot explain, immediately review your extensions and run a security scan. For more information on how fake extensions can spy on your Gmail, read the detailed report from TecMundo about a campaign that used 30 fake AI extensions to spy on 260,000 users. This article explains how the extensions operated and what you can do to avoid falling victim. Similarly, if you are interested in legitimate mail tracking tools, check out the TechTudo article on Mailtrack. It describes how plugins like Mailtrack add read confirmations to Gmail and how they differ from malicious add-ons.
References
TecMundo. Extensoes falsas de IA no Chrome espiavam e-mail e microfone de 260 mil usuarios. Published 2025. Available at: https://www.tecmundo.com.br/seguranca/410688-extensoes-falsas-de-ia-no-chrome-espiavam-e-mail-e-microfone-de-260-mil-usuarios.htm
TechTudo. Mailtrack confirma leitura de mensagem no Gmail, similar ao WhatsApp. Published 2013. Available at: https://www.techtudo.com.br/noticias/2013/11/plugin-para-chrome-confirma-leitura-de-mensagem-no-gmail-similar-ao-whatsapp.ghtml
Google Safety Center. How to manage extensions in Chrome. Available at: https://support.google.com/chrome/answer/169698
