The CloudShark Threat Assessment addon is installed with an initial set of the Emerging Threats Open rules. By default these rules are never updated after the initial installation of the addon. Customers with the Threat Assessment addon may have rules that they have developed or purchased themselves that can be used with CloudShark.
CloudShark uses the configuration files in
determine the rules and variable settings used during a threat assessment.
Suricata is used behind the scenes to generate
threats based on the traffic in the capture file.
suricata-vars.yaml can be modified to configure the variables which
are used in rules. Here is a link describing the Suricata configuration for
suricata-rules.yaml can be modified to point Suricata to files
containing the rules. Here is a link describing the Suricata configuration for
default-rule-path: setting should not be changed and must be set to
/usr/cloudshark/etc/suricata/rules/ for threat assessment to work properly.
Suricata-Update is a tool bundled with Suricata that may be used to download new rules for threat assessment. The command to download and update the Emerging Threats Open rules that were initially installed with CloudShark is:
Suricata-Update can download rules from additional sources such as the ET Pro Ruleset. To view what sources can be used for new rules run the commands:
/usr/cloudshark/bin/suricata-update update-sources /usr/cloudshark/bin/suricata-update list-sources
Additional sources can be enabled by running:
/usr/cloudshark/bin/suricata-update enable-source <source>
Some rulesets such as the ET Pro Ruleset mentioned above may require a subscription and this command will prompt for an access code.
After changing either of these configurations Suricata will have to be reloaded
to use the new variables and rules files. Here is a command that can be run as
cloudshark user to reload Suricata:
cd /var/www/cloudshark/current && bin/run "sc = SuricataConnection.new;sc.send_reload_command"
CloudShark runs the capture through Suricata once and then caches the result
which gets returned on subsequent requests without rerunning the capture
through Suricata. The cache can be invalidated by updating the last modified
date of the file
/usr/cloudshark/etc/suricata/RULES-VERSION. This can be done
using the command
touch /usr/cloudshark/etc/suricata/RULES-VERSION. Then
when a users requests a threat assessment the capture will be rerun using any
new rules or configuration changes to Suricata.