OSSEC
What it is
OSSEC is an open-source host-based intrusion detection system for monitoring systems and network components across multiple platforms. It analyzes logs, checks file integrity, monitors the Windows registry, detects rootkits, and can send real-time alerts or take active responses. Monitoring can use agents or run without them, while a central server manages policies across operating systems with server-specific overrides. Alerts can go through SMTP, SMS, or syslog, and active response can block an attack. These capabilities can help address PCI and HIPAA requirements through file-integrity monitoring, log inspection, and policy enforcement. OSSEC and OSSEC+ use command-line management; Atomic OSSEC editions add a management console. OSSEC+ adds machine learning, ELK integration, community threat sharing, and additional rules. The OSSEC plan is free; OSSEC+ is free with registration. Atomic OSSEC costs $5.00 per month per device. Atomic OSSEC SaaS offers a free 14-day trial for up to 10 endpoints without a credit card.
For and against
For
- Monitors logs, file integrity, registries, and rootkits
- Supports agent-based and agentless monitoring
- Sends alerts through SMTP, SMS, and syslog
- Free OSSEC and OSSEC+ plans are listed
Against
- OSSEC and OSSEC+ use command-line management
- Atomic OSSEC costs $5.00 per month per device
- OSSEC+ requires billed registration
The verdict
OSSEC combines host monitoring, policy management, alerting, and active response, with free plans and paid Atomic editions. The command-line interface in OSSEC and OSSEC+ is an important distinction for readers who want a graphical console.
Who it suits
OSSEC suits teams that need host and network-component monitoring across multiple operating systems, including for PCI or HIPAA requirements. Those wanting a management console or commercial assistance can consider Atomic OSSEC.
Plans and prices
OSSEC
Basic out-of-the-box ruleset · community support · self-hosted
Read 14 Oct 2026 · ossec.net
OSSEC+
Registration required · hundreds of additional rules · machine learning
Read 14 Oct 2026 · ossec.net
Atomic OSSEC
Commercial rules · GUI · vulnerability management · SIEM
Read 14 Oct 2026 · ossec.net
Atomic OSSEC
Volume discounts available · enterprise FIM and compliance features
Read 14 Oct 2026 · atomicorp.com
On the record
- Active response
- Active response runs administrator-defined commands locally or on selected agents when alerts, levels or rule groups match.ossec.net · read 14 Oct 2026
- Agentless monitoring
- The documentation supports agentless monitoring and custom agentless scripts for systems where software installation is restricted.ossec.net · read 14 Oct 2026
- Alert integrations
- SMTP, SMS and syslog integrations can send alerts to email-enabled devices, and active response can block an attack immediately.ossec.net · read 1 Oct 2026
- Alert outputs
- OSSEC documents email, syslog, JSON, database and Prelude output options.ossec.net · read 14 Oct 2026
- API
- Atomic OSSEC advertises a web API and application-protection capabilities.atomicorp.com · read 14 Oct 2026
- Centralized management
- OSSEC provides a centralized management server for policies across multiple operating systems with server-specific overrides.ossec.net · read 1 Oct 2026
- Centralized policy enforcement
- A manager can distribute centralized agent configuration and policy settings.ossec.net · read 14 Oct 2026
- Commercial support
- Atomicorp provides OSSEC deployment assistance and post-sale support services.ossec.net · read 1 Oct 2026
- Compliance
- OSSEC helps address PCI and HIPAA requirements, including file-integrity monitoring, log inspection and policy enforcement.ossec.net · read 1 Oct 2026
- Current release
- OSSEC 4.4.0 was released on October 5, 2026 according to the project homepage.ossec.net · read 14 Oct 2026
- Custom extensibility
- Administrators can write custom decoders and rules and test them with ossec-logtest.ossec.net · read 14 Oct 2026
- Detection capabilities
- OSSEC provides log analysis, file-integrity checking, Windows registry monitoring, centralized policy enforcement, rootkit detection, real-time alerting and active response.ossec.net · read 1 Oct 2026
- Documentation depth
- The manual includes architecture, supported systems, agents, log monitoring, syscheck, rootcheck, rules, decoders, output formats, configuration syntax, man pages and examples.ossec.net · read 14 Oct 2026
- Enterprise integrations
- Atomic OSSEC includes native integrations for AWS, Azure, GCP, Splunk, Arcsight, OpenSearch, ELK, Slack, PagerDuty, Jira, Cloudflare, Amazon S3 and Glacier.ossec.net · read 1 Oct 2026
- File integrity monitoring
- Syscheck hashes monitored files and Windows registry entries with MD5, SHA-1 and SHA-256 and alerts on changes.ossec.net · read 14 Oct 2026
- GetApp feature ratings
- The single GetApp review gives file-integrity monitoring, intrusion detection and log management 5.0 out of 5.getapp.com · read 14 Oct 2026
- GetApp integrations
- GetApp identifies Cloudflare and Slack as reviewed integrations and also lists Microsoft Azure and PagerDuty.getapp.com · read 14 Oct 2026
- GetApp support
- GetApp lists FAQs/forums and phone support for Atomicorp OSSEC.getapp.com · read 14 Oct 2026
