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Lavabit was vulnerable to three attackers: 1) The server operator could choose to obtain access to plaintext. 2) An attacker who compromised the server could g
by moxie 13y ago
Lavabit was vulnerable to three attackers:
1) The server operator could choose to obtain access to plaintext.
2) An attacker who compromised the server could get access to plaintext.
3) Anyone capable of intercepting the SSL communication could get access to plaintext.
Incidentally, those are the exact same points of vulnerability for a normal (unencrypted) mail service.
One interesting question is why the US government requested Lavabit's SSL key rather than just getting a CA to sign their own. My assumption is because they were interested in past communication that might have already been deleted (perhaps by Snowden). We now know that the US government often logs and stores ciphertext, and we know that Lavabit was not selecting PFS SSL cipher suites.
So when Ladar did eventually provide the SSL key to the government, it's likely that the government was able to use that to decrypt all previously stored traffic and obtain the entire history of transmitted email.
So it's quite likely that Snowden (and all other Lavabit users) did have their email read by the government.
- jedbrown 13y agoWhat is different about the government logging traffic between Lavabit and the user versus the SMTP between another host and Lavabit? With Lavabit's key, they can get all incoming mail (and many providers don't even use STARTTLS). Perhaps their logged traffic was incomplete or is difficult to search? Email just isn't very secure as a protocol; people that care need something they can verify, like PGP (which Snowden used). It's unfortunate that the asynchronous nature of email (which we tend to view as an important feature) is incompatible with client-verifiable forward secrecy.
- ju916 13y agoAre you sure, that Lavabit did not select PFS? Is this documented somewhere? That's quite a fumble for someboday advertising secure email services. BTW: shouldn't we assume, that the US government operates at least an own intermediate CA for such purposes rather than getting single Certs signed.
- natevancouver 13y agoLadar says so in this interview, starting around 32:30: http://www.youtube.com/watch?v=7LzKjxj0u_s#t=32m30s http://www.youtube.com/watch?v=7LzKjxj0u_s#t=32m30s