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OSSEC
Unified host-based intrusion detection, log analysis, and response platform
OSSEC provides comprehensive host-based intrusion detection, file integrity monitoring, log analysis, rootkit detection, policy compliance, and real-time alerting with active response capabilities for diverse environments.
Overview
Overview
OSSEC is a comprehensive host‑based intrusion detection system that combines file integrity monitoring, log analysis, rootkit detection, policy compliance checks, and real‑time alerting with active response capabilities. It is written in C and supports a wide range of Unix‑like operating systems as well as Windows agents, making it suitable for heterogeneous environments.
Deployment
The manager can be installed on a dedicated server or container, while agents are deployed on each monitored host. Configuration is performed through plain‑text XML files, allowing fine‑grained rule definition and integration with external SIEMs via syslog or API. Community support is available through Slack, Discord, and the project’s GitHub repository, and regular releases are published on the official website.
Typical users include security analysts, system administrators, and compliance officers who need a low‑cost solution for continuous monitoring. OSSEC’s modular architecture allows integration with existing ticketing systems and custom response scripts, enabling automated containment of threats across the infrastructure.
Highlights
File integrity monitoring with real‑time alerts
Log analysis across multiple platforms
Rootkit and policy compliance detection
Active response scripts for automated remediation
Pros
- Extensive detection coverage (HIDS, log, rootkit)
- Highly configurable and extensible via scripts
- Large community and active support channels
- Works on many Unix‑like systems
Considerations
- Steeper learning curve for complex rule tuning
- Limited native Windows agent compared to Linux
- Console UI is text‑based, no modern web UI
- Resource usage can be high on very busy hosts
Managed products teams compare with
When teams consider OSSEC, these hosted platforms usually appear on the same shortlist.
Looking for a hosted option? These are the services engineering teams benchmark against before choosing open source.
Fit guide
Great for
- Small to medium enterprises needing cost‑effective host security
- Security teams requiring customizable detection rules
- Organizations subject to PCI‑DSS or NIST compliance
- IT admins who prefer open‑source, on‑prem solutions
Not ideal when
- Enterprises that demand a fully managed SaaS SIEM
- Teams without scripting expertise for active response
- Environments requiring a native graphical dashboard
- Very low‑resource devices where overhead must be minimal
How teams use it
Detect unauthorized file changes
Immediate alerts when critical system files are modified, enabling rapid investigation.
Identify brute‑force SSH attacks
Correlates log entries to flag repeated login failures and triggers block actions.
Maintain PCI‑DSS compliance
Monitors required security controls and generates reports to satisfy audit requirements.
Automated malware containment
Rootkit detection triggers active response scripts that isolate the affected host.
Tech snapshot
C87%
Shell7%
Perl3%
Makefile2%
NSIS1%
Python1%
Frequently asked questions
What platforms does OSSEC support?
OSSEC runs on most Unix‑like systems (Linux, BSD, macOS) and provides agents for Windows.
How are alerts delivered?
Alerts can be sent via email, syslog, or integrated with external SIEMs through its API.
Is there a web interface?
OSSEC includes a web UI called Wazuh (a fork) but the core project provides a command‑line interface; third‑party dashboards are available.
Can OSSEC be containerized?
Yes, Dockerfiles are provided, allowing deployment of the manager and agents in containers.
How is the project licensed?
The repository does not specify a license (NOASSERTION), so review the source for licensing details before commercial use.
Project at a glance
Active- Stars
- 5,008
- Watchers
- 5,008
- Forks
- 1,069
Repo age12 years old
Last commit2 days ago
Primary languageC
Last synced yesterday