Does your password manager really need permissions to do anything ever?

Screenshot from 2018-03-03 12-01-59

Almost all password manager’s browser extensions have permission to “Read and change all your data on the websites you visit”. If that sounds scary, it’s because it is. That’s the “<all_urls>” permission. It means the extension is allowed to execute arbitrary JavaScript at any time on any website without warning. Here’s some examples of what I could do if you installed an extension I made with <all_urls>.

  • Run a keylogger on every webpage you visit
  • Inject extra ads into every website
  • Run a password manager that autofills every login form even when you do not ask it to – this is in fact common. This includes malicious forms that might have been injected into a victims website to steal your password.
  • Run a password manager that checks each and every domain you ever visit and forget to sanitize the domain url making it vulnerable to code injection attacks that could lead to a rouge website capturing all of your passwords.
  • If I’m feeling only slightly evil, I simply record each domain you ever visit and sell that data to advertisers.

Passit does not require the <all_urls> permission. This doesn’t make us invulnerable to all extension-based attacks, but it greatly mitigates them. Let’s consider some:

  • “I sell you out (perhaps to another company) and start making my extension serve ads or other garbage” – you’d get a notification about the increased permissions and hopefully you’d check our blog to see why we want scary permissions.
  • “My sloppy code is vulnerable to JS injection attacks” – but because Passit doesn’t run until you invoke it, that probably only happens on websites you already know and trust at least somewhat.

Forget security vs convenience

(Sort of)

Passit has easy to use shortcuts for autofill, so you don’t give up much convenience. I personally don’t find pressing a shortcut key to log in to be a big burden, especially with such nice security gains. Our strategy also means Passit will never have Clippy-esque “Would you like to save this password??” forms because Passit will never bother you until you activate it.

That said, Passit is positioned to be a web-based, easy-to-sync, and share/organization-friendly password manager. I think password managers like pass still offer a benefit for personal use when you don’t care about sharing or autofill. The most secure password manager would be a piece of paper in a safe in a fort. At some point, we have to pick where we are comfortable between security and privacy vs convenience. I hope Passit makes an appealing choice that is nicer to use than programs like pass or KeePass while providing better security and privacy than LastPass or 1Password.

Try Passit out today. Use our free hosted service or run it yourself. If you like it, please star us on Gitlab and report some feature requests or issues.

By David

I am a supporter of free software and run Burke Software and Consulting LLC. I am always looking for contract work especially for non-profits and open source projects. Open Source Contributions I maintain a number of Django related projects including GlitchTip, Passit, and django-report-builder. You can view my work on gitlab. Academic papers Incorporating Gaming in Software Engineering Projects: Case of RMU Monopoly in the Journal of Systemics, Cybernetics and Informatics (2008)

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