Security

What are the default ciphers used for supportSSLV3Only=true

ashrafmr
Engager

If I do not specify a cipherSuite entry explicitly what is used?

For example, is it equivalent to 'SSLv3:!aNULL:!eNULL'?

0 Karma

hsesterhenn_spl
Splunk Employee
Splunk Employee

Hi,

just an update to make sure current options are set: v7.3+

https://docs.splunk.com/Documentation/Splunk/latest/Security/Ciphersuites

HTH,

Holger

0 Karma

MuS
Legend

Hi ashrafmr,

I did some testing with supportSSLV3Only = true and you need to have at least one cipherSuite set in web.conf. If you remove it splunkweb will not start returning this error:

2014-04-10 10:16:39,534 ERROR   [5346535fe020bd8d0] root:555 - 'cipherSuite'
Traceback (most recent call last):
  File "/opt/splunk/lib/python2.7/site-packages/splunk/appserver/mrsparkle/root.py", line 550, in <module>
    run(blocking=True)
  File "/opt/splunk/lib/python2.7/site-packages/splunk/appserver/mrsparkle/root.py", line 250, in run
    ssl_ciphers = str(global_cfg['cipherSuite'])
KeyError: 'cipherSuite'

In your default web.conf there is a cipherSuite entry like this:

# For the HTTP server, Diable ciphers lower than 128-bit and disallow ciphers that
# don't provide authentication and/or encryption.
# Use 'openssl ciphers -v' to generate a list of supported ciphers
cipherSuite = ALL:!aNULL:!eNULL:!LOW:!EXP:RC4+RSA:+HIGH:+MEDIUM

You can check for any overlapping .conf settings (I did not have any) with btool like this:

/opt/splunk/bin/splunk cmd btool --debug web list | grep cipher

If you now open up Splunk in your browser, you will see something like this:

Connection Encrypted: High-grade Encryption (TLS_RSA_WITH_AES_128_CBC_SHA, 128 bit keys)

The message may differ based on your browser (I used Firefox). Based on that the default cipher would be:

AES_128_CBC

On the other hand chrome will display something like this:

TLS 1.0 AES_256_CBC SHA1 RSA

since I did not set any specific cipher in web.conf, it just disables the weak ciphers.

hope this helps ...

cheers, MuS

MuS
Legend

small update, these are the firsts default ciphers used:

ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:SRP-DSS-AES-256-CBC-SHA:SRP-RSA-AES-256-CBC-SHA:DHE-DSS-AES256-GCM-SHA384:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA256:DHE-RSA-AES256-SHA:DHE-DSS-AES256-SHA:DHE-RSA-CAMELLIA256-SHA:DHE-DSS-CAMELLIA256-SHA

the list is much longer and can be see with:

$SPLUNK_HOME/bin/splunk cmd openssl ciphers
0 Karma
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