4 ms·
aren't root CAs installed inside browsers and OSes so that they can't be hijacked without physical access to the target victim device?
by obert 5y ago
aren't root CAs installed inside browsers and OSes so that they can't be hijacked without physical access to the target victim device?
- mindwok 5y agoThe attack (I think) would work like this: - You own the domain trust.org pointing to IP address 2.3.4.5. - Someone performs a BGP hijack on 2.3.4.5 and now hosts their own server on 2.3.4.5. - They then ask Letsencrypt for a certificate to prove they are trust.org. Letsencrypt provides them a token to host on their website to prove they control it. - Letsencrypt does a DNS lookup, sees trust.org resolves to 2.3.4.5, and performs a http request to that website to check for a token which the hijacker has duly placed on their server at 2.3.4.5. - Letsencrypt issues a certificate for trust.org, which is now valid and controlled by the hijacker. None of this requires access to CAs installed on anyones machine, because Letsencrypt is widely trusted and they are the ones issuing the cert.
- kadoban 5y agoWhen the CA is giving you, supposedly the owner of someguy.example, a new certificate, how do they verify that you're you first? One common way is they tell you a magic, unique string and you serve it under someguy.example/.well-known/whatever and they connect to you and verify it's there and matches. But if BGP is being hijacked, when they connect to you, they could really be connecting to some scammer. How would they know? So now some scammer has proved they're you and they'll be given a valid cert for someguy.example. The other common verification methods have similar holes.