| Subject: | strengthening server SSL |
I recently made use of the SSL Pulse tool to report on some of
our https servers. Most of these are apache but I did test
Mojolicious which is a perl event-based server making use of
IO::Socket::SSL.
Before I mention the specific items reported, would it make
sense for the IO::Socket::SSL docs to include a section mentioning
configuration items that could improve security ?
Perhaps one section for client and another for server.
It's the latter I'm most interested in.
Then again maybe there's some debate about the significance
of what they choose to report.
Rather than change current defaults or have other authors
setting up options, maybe you could add something like:
use_more_secure_server_defaults
That's if you were happy accepting that responsibility.
One advantage of providing such functionality could be
if the best options needed to be based on the openssl
version/capabilities.
So on RHEL5 with OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008.
perl 5.14.2, IO::Socket::SSL 1.62, Net::SSLeay 1.47,
Mojolicious 2.8.5
https://www.ssllabs.com/ssltest/analyze.html?d=mojo-ssl-test.its.uq.edu.au
TLS 1.2 No
TLS 1.1 No
SSL 2.0 INSECURE
SSL_RC4_128_EXPORT40_WITH_MD5 (0x20080) WEAK
SSL_RC2_128_CBC_EXPORT40_WITH_MD5 (0x40080) WEAK
SSL_DES_64_CBC_WITH_MD5 (0x60040) WEAK
TLS_RSA_WITH_DES_CBC_SHA (0x9) WEAK
Session resumption No (IDs assigned but not accepted)
BEAST attack Vulnerable INSECURE (more info)
Secure Renegotiation Supported, with client-initiated renegotiation enabled DoS
DANGER (more info)
The first 2 slightly reduce the rating but are not considered
significant because a lot of deployed software doesn't
support versions of TLS past 1.0
The WEAK ciphers were removed by adding this to mojolicious
SSL_cipher_list => 'ALL:!LOW:!EXP:!ADH',
taken from IO::Socket::SSL docs
However attempts to remove SSLv2 by trying things like this
in the options mojolicious uses
SSL_version => 'SSLv3',
SSL_version => 'TLSv1',
SSL_version => 'SSLv3 TLSv1',
SSL_version => '!SSLv2,SSLv3,TLSv1', # based on OpenSSL docs
didn't work. In fact the first 2 resulted in the mojolicious
server not responding to https. That could be a problem with
that software, but is there some way to be as flexible with
SSL_version as openssl itself is, as is the case with
SSL_cipher_list ?
If that was the case you could use something like
SSL_version => '-ALL -SSLv2 +SSLv3 +TLSv1'
However I think
Session resumption
BEAST attack
Secure Renegotiation
need low-level access and I'm not sure Net::SSLeay provides all
of these, e.g. BEAST mitigation requires the server to use
it's cipher order rather than what client offers.