SIEMonster is described as 'A very powerful and well documented open source SIEM with options to purchase support packages'. There are six alternatives to SIEMonster for a variety of platforms, including Linux, Online / Web-based, Windows, Mac and Self-Hosted solutions. The best alternative is Splunk, which is free. Other great apps like SIEMonster are Prelude (Free, Open Source), AlienVault (Freemium), Gravwell (Freemium) and IQLECT (Freemium).
Splunk is software that provides unique visibility across your entire IT infrastructure from one place in real time. Only Splunk enables you to search, report, monitor and analyze streaming and historical data from any source.
Prelude is a Universal Security Information & Event Management (SIEM) system. It collects, normalizes, sorts, aggregates, correlates and reports all security-related events independently of the product brand or license giving rise to such events.
Alienvault integrates and correlates many popular network and security monitoring tools in one suite, inlcuding OSSEC, nfdump, log analyzers, nagios, and nessus and analyzes it against its own community-driven threat feed.
IQLECT is the creator of Ampere, a real-time big data analytics platform. Various apps for data center infrastructure monitoring, clickstream analysis, log analysis and others can be deployed on the platform.
ANET SureLog SIEM consolidates log source event data from thousands of devices endpoints and applications distributed throughout a network. It performs immediate normalization and correlation activities on raw data to distinguish real threats.