Comment by codedokode
3 years ago
This doesn't mean you should use unsecure methods instead and issue certificates to anyone capable to do MitM.
3 years ago
This doesn't mean you should use unsecure methods instead and issue certificates to anyone capable to do MitM.
How could Letsencrypt even verify a server setup if not via DNS/HTTP? Also, verify against what? The servers are basically random strangers without identity when they first talk to LE.
In this case there has been a valid certificate for the site; this alone should raise suspicion.
Also, if they cannot do secure validation then maybe they should stop issuing certificates for sites that already have a proper certificate.
This happens all the time when a server is rebuilt from scratch - same cert using a different keypair.
6 replies →
Over the DNS challenge, of course.
This is exactly the same as all other CA's do this.... for DV-certificates you basically place a key/special file on the webserver, or receive a verficiation code via (plaintext) email.
For EV certs there might be more validation, but users will never see the difference between EV and DV certificates.
So SSL certificates are completely unreliable; we should only wait until Russian or Chinese comrades find a good use for this attack (e.g. temporary redirecting Western traffic using BGP to validate a Let's Encrypt's cert for Western site).
yes? this is a well-known problem, which is why CAA-ACME etc and certificate transparency logs exist.