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Autofill Exposure Auditor - Test Your Browser

Zero-Trust Utilities

Test Your Browser's Autofill Exposure

Many websites use "hidden" form fields to harvest more data than you realize when you use your browser's Autofill feature.

100% Client-Side • No Data is Saved or Transmitted

How this attack works

When you use Browser Autofill, the browser looks for common field names (like "address" or "phone") in the autoComplete attribute of <input> tags.

Malicious websites can include these fields but hide them using CSS (making them invisible or off-screen). When you autofill your name and email, the browser helpfuly fills the hidden fields too, allowing the site to "steal" your home address, phone number, and more without you ever typing them.

Security Tip: Only use Autofill on trusted websites, or consider using a password manager that prompts you before filling individual sensitive fields.

What is Autofill Exposure Auditor - Test Your Browser?

Autofill Exposure Auditor is an educational security simulator that demonstrates a common web privacy vulnerability: hidden field harvesting. Modern browsers offer an 'Autofill' feature that saves time by filling in your address, phone number, and credit card info. However, malicious sites can exploit this by including fields you can't see (hidden by CSS). When you autofill a simple 'Email' field, your browser might also fill in your home address or phone number into these hidden fields without your knowledge.

How it works

The tool renders a form with two visible fields (Name and Email) and several invisible fields (Address, Phone, etc.) using the standard `autoComplete` attributes. When you submit the form, our script inspects the values of all fields - visible and hidden. Since the processing is entirely client-side, your data is never sent to our server; it is only displayed back to you to show what was captured.

Features & Benefits

  • Educational: see exactly how hidden fields harvest your personal data
  • Interactive: runs a real simulation in your browser
  • Actionable: learn how to protect yourself from autofill harvesting

Frequently Asked Questions

Is my data safe?

Yes. The tool runs 100% in your browser. No data is stored, logged, or transmitted. The values stay in your browser's memory until you refresh the page.

How do I stop this from happening?

Disable Autofill in your browser settings, or use a password manager that requires explicit permission for each field it fills.

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Learn More & Guides

The Invisible Form Attack: How Your Browser's Autofill Can Leak Sensitive Data

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