since no support for compression and support for renegotiation are
necessary for the server to have a secure configuration, collect
and report those two too
since the signature and hash algorithm in TLSv1.2 is selectable by server
and negotiated using TLS extensions, we can check what sig algs is
the server willing to perform and whatever it does honour client
selection
it also tests what happens if the client doesn't offer any sigalgs that
are necessary to use the ciphers selected by server
buggy servers may choke on large ClientHello's, TLSv1.2 ClientHello's,
etc. try to detect such failures and report them
among tried connections are TLS1.2, TLS1.1, TLS1.0 and SSLv3 with
ability to downgrade to lower protocol versions as well as a size
limited client hello, both TLS1.2 and TLS1.0 version
EXP is self explanatory - export grade
DES-CBC3-MD5 is available only in SSLv2 - not secure
RC4-64-MD5 is also a weakened version (though not marked as export grade)
since early versions of 1.0.2 openssl supports -curves command line
option, it allows us to set the curves advertised as supported
use the same approach to testing: advertise all, check what server
accepts, remove the accepted from list, repeat. When server aborts
connection or selects non ECC cipher, we know that we've tested all.
it's relatively easy to make the cipher selection generic,
so that adding different clients is as easy as converting their
client hello cipher ordering to openssl cipher names
since now we know if server honours client order or not, we can use it
to properly simulate handshakes for a given client, also report
the general stats of this server configuration variable
the ECDH parameters come from server certificate - the point
on elliptic curve. The RSA comes from the signature on the certificate
which comes from CA
While preferring RC4 in TLS1.0 or SSL3 was recommended before,
it was always known that TLS1.1 and TLS1.2 were not vulnerable against
BEAST, so forcing RC4 there is a mistake. Report number of such servers.
Two interesting server configurations are ones that support
only SSL3 or TLS1 only (old, but otherwise correctly configured servers)
and ones that support only TLS1.1 or up (brave admins that support
only new clients)
Hubert Kario
Hubert Kario
Julien Vehent
Hubert Kario