At DEF CON 33, independent security researcher Marek Tóth revealed a new class of attack called DOM-based extension clickjacking that can manipulate browser-based password managers and, in limited scenarios, hijack passkey authentication flows. This is not a failure of cryptography itself, but a breakdown in the layers surrounding it.
What is being attacked, and how?
Clickjacking is not new. In its classic form, an attacker overlays a transparent frame or control on a visible page so that a user thinks they are clicking one thing but actually triggers another.
What Tóth’s technique adds is the targeting of browser extensions’ UI elements specifically, the autofill prompts that password managers inject into web pages. The attacker’s script controls the page’s Document Object Model (DOM) and applies CSS tricks (such as setting opacity to zero or overlaying fake elements) so that a user’s genuine click (for example, “Accept cookies”) also activates that hidden autofill element. The result: the extension may populate fields transparently, then the attacker reads the filled data.
In many of Tóth’s tests, a single click was sufficient to trigger data leakage credentials, TOTP codes (2FA), credit card information, or personal data. In some setups, passkey workflows could also be subverted using “signed assertion hijacking,” if the server did not enforce session-bound challenges.
This article has been indexed from CySecurity News – Latest Information Security and Hacking Incidents