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Issue 733468 link

Starred by 2 users

Issue metadata

Status: WontFix
Owner: ----
Closed: Jun 2017
EstimatedDays: ----
NextAction: ----
OS: Mac
Pri: 2
Type: Bug-Security



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iframe can receive event even box-shadow laying over it

Reported by nju...@gmail.com, Jun 15 2017

Issue description

UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36

Steps to reproduce the problem:
This is a example:
(I'm sorry I haven't found a popular english site allowing embedded in frame)
https://jsfiddle.net/renaesop/4fhpy2ay/9/

What is the expected behavior?

What went wrong?
Attacker can easily embed a defenseless site in an iframe, and cover other contents over the iframe. Normally, the iframe cannot respond to user's action, but if attacker uses box-shadow to cover the iframe, click the box-shadow area will be treated as click the item in the iframe!

Did this work before? N/A 

Chrome version: 58.0.3029.110  Channel: stable
OS Version: OS X 10.12.5
Flash Version:
 

Comment 1 by nju...@gmail.com, Jun 15 2017

seems the same issue with "mouseevent none"

Comment 2 by est...@chromium.org, Jun 15 2017

Labels: -Restrict-View-SecurityTeam Security_Impact-None
Status: WontFix (was: Unconfirmed)
Thanks for the report. This attack is known as clickjacking. Sites can protect themselves from it by serving the X-Frame-Options header (https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options) to instruct the browser not to frame them.
On a related note, while this does repro in 58.0.3029.110, it no longer repros as of 61.0.3131.0; the box shadow consumes the click event. As noted in Comment #2, however, there are numerous other mechanisms that allow clickjacking frames that do not use X-Frame-Options or Content-Security-Policy's FrameAncestors directive.

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