Isolation by Default

Transcript

1. Isolation by Default XSLeaks Summit 2020-12-01 — Camille Lamy &

   Mike West

2. Status quo ante:

3. Status quo: Well-informed developers will adopt CORP, XFO, COOP, and

   COEP. Less-informed developers remain vulnerable.

4. The Future? Browsers will isolate documents by default. Developers who

   require cross-origin collaboration can opt-out of isolation.

5. A Few Modest Proposals User agents should: 1. Apply COOP:

   same-origin-allow-popups by default: https://github.com/mikewest/coop-by-default/ 2. Require embedees to opt-into framing rather than out of it: https://github.com/mikewest/embedding-requires-opt-in/ 3. Deprecate and remove impediments to origin isolation by default (most notably document.domain: https://github.com/mikewest/deprecating-document-domain)

6. A Few More Modest Proposals User agents should: 4. Require

   opt-in for communication across network boundaries: https://wicg.github.io/cors-rfc1918/ 5. Shift towards credentiallness requests by default (SameSite=Lax on the one hand, COEP: x-bikeshed-credentialless-unless-cors on the other): https://github.com/mikewest/credentiallessness/ 6. Strict MIME type checking, in conjunction with CORB/ORB.

7. What else should we try to break fix?