SPLUNK free on Centos
http://linoxide.com/monitoring-2/install-splunk-centos-7/
OSSIM
http://linoxide.com/security/install-configure-alienvault-siem-ossim/
To recover the Admin password (eg. the password for the web interface) on a v7.7.2.x Siem installation, you can use the command:
# /opt/qradar/support/changePasswd.sh -a
# /etc/init.d/tomcat restart