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Prevents Users From Pasting Into Password Fields

Overview

Some websites claim that preventing users from pasting passwords somehow improves security. In Let Them Paste Passwords, the National Cyber Security Centre says that this claim is unfounded.

Password pasting improves security because it enables users to use password managers. Password managers typically generate strong passwords for users, store them securely, and then automatically paste them into password fields whenever users need to log in.

See The "Cobra Effect" That Is Disabling Paste On Password Fields for more on why enabling pasting is a better security practice.

Recommendations

Remove the code that's preventing users from pasting into password fields. It's probably a call to preventDefault() within the paste event listener that's associated to the password input element.

let input = document.querySelector('input');
input.addEventListener('paste', (e) => {
  e.preventDefault(); // This is what prevents pasting.
});

Find and inspect the code that's preventing pasting

To quickly find and inspect the code that's preventing pasting, try enabling the Clipboard > paste checkbox in the Event Listener Breakpoints section of Chrome DevTools, then pasting into a password field. DevTools should pause on the first line of code in the paste event listener.

More information

Lighthouse gathers all <input type="password"> elements, pastes some text into each element, and then verifies that the element's content has been set to the pasted text. If a page doesn't use <input type="password"> for its password input fields, Lighthouse doesn't detect those elements. It's also possible to prevent pasting outside of a paste event listener. Lighthouse doesn't detect that scenario, either.

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