Summary

Multiple password managers can be tricked into auto-filling credentials into untrusted pages. This can lead to account compromise for any users using these password managers.

Severity

High - This vulnerability leverages password managers to auto-fill credentials into untrusted pages, without the master password.

Proof of Concept

1. Go to https://coop.xss.guru/sign-in and enter credentials
2. Have the password manager save the credentials
3. Go to https://coop.xss.guru/sign-in-alt and confirm that the password manager autofills the credentials as expected
4. Go to https://coop.xss.guru/sign-in-phish-csp-sandbox: The password manager should not auto-fill credentials since the page has a CSP sandbox response header
5. Go to https://coop.xss.guru/sign-in-phish-iframe-sandbox: The password manager should not auto-fill credentials since the form is inside of a sandboxed iframe

Further Analysis

Password managers should check whether content is sandboxed before auto-filling credentials. This can be done in many ways, but one way is to check self.origin of a page and refusing to fill in credentials if self.origin is "null".

1. Bitwarden: Vulnerable - Bitwarden was found to auto-fill credentials into both types of sandboxed content as soon as the user clicked on the Bitwarden chrome extension. Fixed and released on 12/14/2022.
2. DashLane: Vulnerable - DashLane immediately auto-fills credentials into the CSP sandboxed page. It displays a warning box before auto-filling credentials into the sandboxed iframe. Fixed and released on 12/2/2022.
3. Safari: Vulnerable - Safari auto-fills credentials into both types of sandboxed content though user interaction is required.
4. LastPass: Secure
5. 1Password: Secure
6. Chrome: Secure
7. Edge: Secure

Timeline

Date reported: 10/19/2022, Vulnerability reported to Apple on 1/18/2023
Date fixed: Fixed in Bitwarden (12/14/2022) and DashLane (12/2/2022)
Date disclosed: 1/17/2023