IP and DNS Leaks in WebKit Affecting Proxy Browsers and Apple iCloud Private Relay
- WebKit-based browsers on iOS and macOS can be configured to route all web traffic through proxy servers, which is how Tor browsers on iOS and our own Psylo work.
- We found three WebKit features — DNS prefetching, WebAuthn Related Origin Requests, and WebTransport — that bypass the configured proxy and send traffic directly from the device, which exposes the user’s real network.
- The same leaks also affect Apple’s iCloud Private Relay.
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- WebKit-based browsers on iOS and macOS can be configured to route all web traffic through proxy servers, which is how Tor browsers on iOS and our own Psylo work.
- We found three WebKit features — DNS prefetching, WebAuthn Related Origin Requests, and WebTransport — that bypass the configured proxy and send traffic directly from the device, which exposes the user’s real network.
- The same leaks also affect Apple’s iCloud Private Relay.
Sources: Mysk