3 ms·

Applications are the real "end" in end to end, and TLS is already e2e. Good TLS does thwart this attack; an attacker still can't generate a valid certificate.

Applications are the real "end" in end to end, and TLS is already e2e. Good TLS does thwart this attack; an attacker still can't generate a valid certificate. It's taken a lot of focus and attention to make TLS reliable enough to make it a default in browsers, and DNSSEC is not particularly close. DNSSEC supports out-of-date cryptography and has no negotiation mechanisms to avoid them, which makes it very hard to use as a default e2e security protocol. It also doesn't encrypt anything.

tolleydbg 7y ago
Yes, it is correct that you cannot easily hijack connections that use TLS, but you can make inferences about active connections that use TLS. This is still fairly devastating for a large number of vulnerable users that rely on VPNs in nations with authoritarian information controls.
tssva 7y ago
e2e TLS guarantees that you received a DNS answer from the DNS server you requested it from, no one was able to see the answer in transport and no one was able to change the answer in transport. It doesn't validate that the answer provided was correct according to the owner of the domain your query was regarding. DNSSEC tries to provide this validation. Roughly it is similar to signing a message with PGP. You can argue that DNSSEC is not up to today's crypto standards and no longer trustworthy for its intended purpose, but without some protocol which provides the guarantees DNSSEC tries too e2e encryption is a 1/2 solution to DNS security.
- tptacek 7y ago
  The parent commenter definitely understands what DNSSEC is. His point is that DNSSEC doesn't work the way you appear to think it does. Conceptually, it's meant to prove that a DNS record in a response is actually a record created by the owner of the zone. But in practice, the cryptographic signature isn't valuable to stub resolvers on the end system; instead, end systems trust their "DNS servers" (their resolving cache server) to perform DNSSEC validation for them. The success of that validation is conveyed in a single "AD" bit in the header of the DNS response. Since this attack happens from a vantage point in between the end system and the resolving cache, DNSSEC isn't in play; the attacker will simply set the AD bit in their responses.

tolleydbg 7y ago

Yes, it is correct that you cannot easily hijack connections that use TLS, but you can make inferences about active connections that use TLS. This is still fairly devastating for a large number of vulnerable users that rely on VPNs in nations with authoritarian information controls.

tssva 7y ago

e2e TLS guarantees that you received a DNS answer from the DNS server you requested it from, no one was able to see the answer in transport and no one was able to change the answer in transport. It doesn't validate that the answer provided was correct according to the owner of the domain your query was regarding. DNSSEC tries to provide this validation. Roughly it is similar to signing a message with PGP. You can argue that DNSSEC is not up to today's crypto standards and no longer trustworthy for its intended purpose, but without some protocol which provides the guarantees DNSSEC tries too e2e encryption is a 1/2 solution to DNS security.

tptacek 7y ago
The parent commenter definitely understands what DNSSEC is. His point is that DNSSEC doesn't work the way you appear to think it does. Conceptually, it's meant to prove that a DNS record in a response is actually a record created by the owner of the zone. But in practice, the cryptographic signature isn't valuable to stub resolvers on the end system; instead, end systems trust their "DNS servers" (their resolving cache server) to perform DNSSEC validation for them. The success of that validation is conveyed in a single "AD" bit in the header of the DNS response. Since this attack happens from a vantage point in between the end system and the resolving cache, DNSSEC isn't in play; the attacker will simply set the AD bit in their responses.