Passwords and FIDO2 Are Meant To Be Secret: A Practical Secure Authentication Channel for Web Browsers

Fuente: arXiv
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Main Authors: Gautam, Anuj, Yadav, Tarun, Smith, Garrett, Seamons, Kent, Ruoti, Scott
Format: Preprint
Published: 2025
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author Gautam, Anuj
Yadav, Tarun
Smith, Garrett
Seamons, Kent
Ruoti, Scott
author_facet Gautam, Anuj
Yadav, Tarun
Smith, Garrett
Seamons, Kent
Ruoti, Scott
contents Password managers provide significant security benefits to users. However, malicious client-side scripts and browser extensions can steal passwords after the manager has autofilled them into the web page. In this paper, we extend prior work by Stock and Johns, showing how password autofill can be hardened to prevent these local attacks. We implement our design in the Firefox browser and conduct experiments demonstrating that our defense successfully protects passwords from XSS attacks and malicious extensions. We also show that our implementation is compatible with 97% of the Alexa top 1000 websites. Next, we generalize our design, creating a second defense that prevents recently discovered local attacks against the FIDO2 protocols. We implement this second defense into Firefox, demonstrating that it protects the FIDO2 protocol against XSS attacks and malicious extensions. This defense is compatible with all websites, though it does require a small change (2-3 lines) to web servers implementing FIDO2.
format Preprint
id arxiv_https___arxiv_org_abs_2509_02289
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Passwords and FIDO2 Are Meant To Be Secret: A Practical Secure Authentication Channel for Web Browsers
Gautam, Anuj
Yadav, Tarun
Smith, Garrett
Seamons, Kent
Ruoti, Scott
Cryptography and Security
Password managers provide significant security benefits to users. However, malicious client-side scripts and browser extensions can steal passwords after the manager has autofilled them into the web page. In this paper, we extend prior work by Stock and Johns, showing how password autofill can be hardened to prevent these local attacks. We implement our design in the Firefox browser and conduct experiments demonstrating that our defense successfully protects passwords from XSS attacks and malicious extensions. We also show that our implementation is compatible with 97% of the Alexa top 1000 websites. Next, we generalize our design, creating a second defense that prevents recently discovered local attacks against the FIDO2 protocols. We implement this second defense into Firefox, demonstrating that it protects the FIDO2 protocol against XSS attacks and malicious extensions. This defense is compatible with all websites, though it does require a small change (2-3 lines) to web servers implementing FIDO2.
title Passwords and FIDO2 Are Meant To Be Secret: A Practical Secure Authentication Channel for Web Browsers
topic Cryptography and Security
url https://arxiv.org/abs/2509.02289