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CSS Working Group Editor Drafts
https://drafts.csswg.org/
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Privacy considerations for detectability of assistive technology using CSS #6155

Open ShivanKaul opened 3 years ago

ShivanKaul commented 3 years ago

PING recently reviewed the WAI-ARIA 1.2 spec (https://github.com/w3c/aria/issues/1371) and suggested adding a privacy considerations section (none exists right now) discussing how aria-hidden can be used in combination with JS to heuristically reveal that a user is using assistive technology. In the ensuing discussion, it was brought up that several web technologies, including CSS, can be used heuristically to detect AT (please see https://github.com/w3ctag/design-principles/issues/293).

@alice pointed out that the content-visibility spec has discussion about this risk - could there be similar text for other CSS specs? Would it be useful?

frivoal commented 3 years ago

In principle, yes. If something introduces (or compounds) security/privacy/accessibility considerations, the spec should probably mention it, and cover adequate mitigation. That said, I think that besides agreement on the general principle, this needs to be treated as individual issues per spec (or per feature), as each individual situation needs to be assessed separately.

cookiecrook commented 3 years ago

The simplest method I'm aware of is: <a href="/confirm_at" tabindex="-1" style="position: absolute; left: -9999px;">only AT users or bots will click this link</a> Changing the way positioning works is not an option, so a note related to the positioning properties may be warranted.

cookiecrook commented 3 years ago

Obviously there are several media features in the CSS MQ spec, too. A few that could be used to infer accessibility settings, but more that could be used for device fingerprinting.