Top 5 Open-Source Cloud Security Tools You Need to Know in 2025

In this guide, we’re highlighting five of the most impactful open-source tools that help security and platform teams identify, monitor, and respond to vulnerabilities across the cloud lifecycle. Whether you’re scanning infrastructure as code before deployment, monitoring runtime workloads for threats, or continuously auditing your cloud configuration, these trusted tools offer high-impact, free-to-use solutions.

1. Prowler: Your Multi-Cloud Security Auditor

Source Repo | 11.5k ⭐ Apr 2025

Cloud security engineers and compliance teams rely on Prowler to assess and continuously improve their cloud security posture. Designed for auditing AWS, Azure, GCP, and Kubernetes environments, Prowler checks configurations against best practices and regulatory standards like CIS, NIST, and GDPR—making it a trusted tool for teams responsible for cloud governance and compliance.

Key Features:

• Multi-Cloud Support: Works seamlessly with AWS, Azure, GCP, and Kubernetes
• Extensive Checks: Performs hundreds of security checks based on industry standards and compliance frameworks like CIS, NIST, GDPR, and HIPAA
• Continuous Monitoring: Enables ongoing security assessments to catch issues as they emerge
• Incident Response Capabilities: Provides critical visibility when investigating security incidents
• Hardening Guidance: Delivers actionable recommendations to strengthen your cloud security posture

Why it’s a Top Tool:

Prowler’s comprehensive platform coverage and ability to evaluate your environment against established security benchmarks make it invaluable for understanding and continuously improving your overall cloud security posture. Its actionable insights bridge the gap between compliance requirements and practical security implementation.

2. Trivy: Fast and Comprehensive Vulnerability Scanner

Source Repo | 25.4k ⭐ Apr 2025

DevOps and platform engineers use Trivy to quickly scan containers, infrastructure-as-code, and application artifacts for vulnerabilities before they reach production. Trivy is a fast, all-in-one open-source scanner that fits seamlessly into CI/CD workflows and supports a wide range of file types and cloud-native formats. It’s especially useful for identifying CVEs, misconfigurations, and exposed secrets early in the development lifecycle.

Key Features:

• Versatile Scanning: Scans container images, local file systems, and Git repositories with equal precision
• Vulnerability Detection: Identifies known vulnerabilities in OS packages and application dependencies
• Misconfiguration Scanning: Detects security misconfigurations in container images and infrastructure as code (IaC)
• Secret Scanning: Uncovers accidentally embedded secrets like API keys and passwords
• SBOM Generation: Creates Software Bill of Materials (SBOMs) for enhanced visibility into your software supply chain

Why it’s a Top Tool:

Trivy’s lightning-fast performance and seamless integration into CI/CD pipelines make it a favorite among developers and security teams committed to shifting security left. By identifying vulnerabilities early in the development process, Trivy helps ensure that only secure containers reach production environments.

3. Wazuh: Unified Security Monitoring and Threat Detection

Source Repo | 12.1k ⭐ Apr 2025

Security operations teams use Wazuh to centralize log analysis, detect threats, and monitor cloud and on-prem infrastructure for vulnerabilities and policy violations. Combining SIEM, intrusion detection, and file integrity monitoring in one open-source platform, Wazuh helps teams stay on top of incidents and maintain compliance in complex environments.environments.

Key Features:

• Comprehensive Monitoring: Delivers advanced log analysis, file integrity monitoring, rootkit detection, and active response capabilities
• Cloud Security Monitoring: Specifically tailored to monitor AWS, Azure, and GCP services
• Vulnerability Detection: Identifies software vulnerabilities across your systems
• Threat Intelligence: Correlates security events with threat intelligence feeds to identify known threats
• Incident Response: Equips security teams with tools to effectively respond to and remediate security incidents

Why it’s a Top Tool:

Wazuh’s integration of multiple security functions into a single platform creates a unified view of your security posture, dramatically simplifying threat detection and response across your entire infrastructure. This consolidated approach makes it easier to identify patterns and respond to threats before they escalate.

4. Checkov: Shift-Left Security for Infrastructure as Code

Source Repo | 7.5k ⭐ Apr 2025

DevSecOps and platform teams use Checkov to prevent insecure infrastructure from being deployed by scanning infrastructure-as-code for misconfigurations and compliance violations. Supporting Terraform, CloudFormation, Kubernetes, and other IaC formats, Checkov makes it easy to catch potential issues early and enforce policy-as-code across cloud deployments.

Key Features:

• IaC Coverage: Supports Terraform, CloudFormation, Kubernetes, ARM, and other IaC formats.
• Security and Compliance Checks: Scans for misconfigurations and evaluates against frameworks like CIS, NIST, and SOC 2.
• CI/CD Integration: Seamlessly integrates into DevOps pipelines for early detection of issues.
• Custom Policies: Allows users to define custom policies using Python or Rego (OPA).
• Visual Reports: Generates human-readable and machine-parsable output formats, including JSON, JUnit, and SARIF.
  

Why it’s a Top Tool:
Checkov empowers teams to “shift left” by identifying misconfigurations and compliance violations before deployment, reducing the risk of vulnerable infrastructure reaching production. Its broad IaC support and integration flexibility make it a go-to choice for DevSecOps and platform teams.

5. Falco: Real-Time Runtime Security for Containers and Kubernetes

Source Repo | 7.8k ⭐ Apr 2025

Security engineers and SREs turn to Falco for real-time visibility into suspicious or unexpected behavior inside containers and Kubernetes clusters. As a cloud-native runtime security tool, Falco monitors system calls using eBPF or kernel modules and alerts on activities like shell access, file tampering, and unauthorized network connections—helping teams detect threats as they happen.

Key Features:

• Syscall Detection Engine: Uses eBPF or a kernel module to monitor low-level system activity.
• Behavioral Rules: Detects suspicious activity such as unexpected network connections, file changes, or shell executions.
• Kubernetes-Aware: Can detect policy violations like containers running as root or accessing sensitive volumes.
• Flexible Alerts: Sends alerts via Slack, email, webhooks, or SIEM integrations.
• Custom Rules Engine: Security teams can define custom detection rules based on their threat models.

Why it’s a Top Tool:
Falco brings real-time visibility into what’s happening inside your workloads, filling the critical gap between build-time scanning and full-blown incident response. Its lightweight footprint and deep Kubernetes integration make it a must-have for securing production environments.

Conclusion

These five open-source tools represent a strong foundation for any cloud security team focused on reducing risk through vulnerability detection and real-time monitoring. By combining pre-deployment scanning (like Checkov and Trivy), post-deployment auditing (like Prowler and Wazuh), and runtime threat detection (like Falco), teams can build a layered, cost-effective cloud security posture.

No single tool does it all, but together, these OSS solutions help you gain visibility, catch issues early, and respond faster without breaking your budget.

Honorable Mentions

While our top five tools offer a solid foundation for cloud security, there are several other excellent open-source tools deserve recognition:

• k9 Security IaC: Enforce least privilege access to data in AWS using policy generators for Terraform (S3, KMS) and AWS CDK (S3, KMS, DynamoDB, SQS)
• OpenVAS: A comprehensive vulnerability scanner that identifies a wide range of security weaknesses in your infrastructure
• OWASP ZAP (Zed Attack Proxy): A popular web application security scanner for finding vulnerabilities in your web applications and APIs
• Snort: A widely deployed network intrusion detection and prevention system (NIDS/IPS) for real-time traffic analysis
• Suricata: A high-performance NIDS/IPS engine with multi-threading and advanced features for network security monitoring
• Scout Suite: A multi-cloud security auditing tool for gaining visibility into your security posture across various cloud providers
• CloudQuery: A tool that transforms cloud infrastructure data into a queryable format using SQL, enabling powerful analysis and insights
• Cloud Custodian: Define policies as code to manage and enforce security, cost, and compliance controls across cloud environments. Especially useful for automatically tagging resources, shutting down noncompliant services, or flagging drift from baseline configurations.
• Steampipe: A powerful CLI tool using SQL to query cloud resources across multiple providers
• Cloudsplaining: An AWS IAM security assessment tool that identifies violations of least privilege
• CloudMapper: A tool for analyzing AWS environments by generating network diagrams and security audit reports