Open source cloud security tools offer organizations the flexibility, visibility, and shared expertise needed to keep pace with evolving threats. They are defined by transparency, collaboration and community-driven innovation.
In a landscape where infrastructure spans multiple clouds and workloads shift dynamically, the best defence is no longer built behind closed doors. From runtime protection to cloud-native policy enforcement, these tools are shaping how security teams defend modern cloud environments.
Below are nine essential open source cloud security tools for 2025, each showcasing the power of community-driven innovation. Whether you’re building out a zero-trust architecture, automating compliance, or strengthening container security, these tools will help you secure your cloud stack with the value of open collaboration.
1. Cloud security posture management (CSPM) — Open Policy Agent (OPA)
A CSPM tool is constantly scanning or monitoring for misconfiguration issues and compliance risks that might be lurking in your cloud setup. With businesses widely adopting public and multi-cloud services, keeping up with emerging security risks can be a real headache. CSPM tools ease that burden by automatically detecting and addressing misconfigurations across cloud assets, such as Amazon EC2 instances. This proactive approach lets you spot and fix security gaps before they can be exploited, giving you a crucial edge in maintaining a secure cloud environment.
Open Policy Agent (OPA)
OPA is an open source CSPM tool that enables you to define and enforce fine-grained access controls and security policies across your entire cloud stack. It uses a declarative language called Rego, allowing you to express rules for everything from Kubernetes admission controls to API authorization and infrastructure configuration.
By decoupling policy from application code, OPA makes policy management scalable and flexible. This helps ensure that security rules remain consistent, even as cloud infrastructure evolves. Its wide integration support and ability to enforce policies in real time make it a reliable tool for CSPM and cloud-native governance.
2. Cloud workload protection and Kubernetes security — Falco
A cloud workload protection platform (CWPP) is an automated, real-time security solution that protects workloads running both on-premises and in hybrid cloud environments, including Kubernetes clusters, containers, and virtualized systems. A CWPP protects workloads by actively scanning them for vulnerabilities prior to deployment, and by providing ongoing runtime protection to address emerging threats. Runtime protection scans running processes for active attack indicators. Monitoring for suspicious behaviors in your workloads helps defend against targeted attacks and zero-day exploits.
Falco
Created by Sysdig, Falco is an open source, cloud-native security tool that provides runtime protection across hosts, containers, Kubernetes, and cloud environments. It detects anomalies and suspicious activity by tapping into Linux kernel events and other data sources through community-created plugins, enriching them with contextual metadata for real-time threat detection.
Falco’s custom rules let you spot everything from unexpected network connections to container privilege escalations, helping you detect and respond to threats as they happen. Sysdig also uses Falco rules as the foundation of the Sysdig Secure detection engine, bringing open source innovation to enterprise-grade cloud security.
3. Infrastructure as Code (IaC) security — Checkov
Infrastructure-as-Code has become a core component of IT provisioning and administration strategies across environments of all types. Whether you run applications in the cloud, on-premises, or a combination thereof, IaC is critical for automating infrastructure setup and application deployment at scale. Put simply, IaC is an approach to setting up IT environments in which engineers write machine-readable policy files that define how resources should be configured, as opposed to configuring each resource manually.
However, misconfigured IaC templates can introduce serious security risks at scale, such as exposing sensitive data, creating overly permissive access controls, or leaving workloads unprotected. Checkov helps you address this risk.
Checkov
Checkov helps you catch vulnerabilities before they hit production by scanning IaC configurations for misconfigurations. It supports platforms like Terraform, CloudFormation, and Kubernetes, detecting security risks in your manifests and templates.
With its common command-line interface (CLI), Checkov makes it easy to manage and analyze scan results across multiple frameworks, including Helm, ARM Templates, and Serverless frameworks. It flags issues like insecure access controls, policy violations, and compliance gaps, empowering you to harden your IaC with automated security checks.
4. Identity and access management (IAM) — Keycloak
In cloud environments, IAM is the foundation of controlling who gets access to what. It governs how users, applications, and services authenticate and what actions they’re authorized to perform. IAM policies also define permissions, roles, and access rules to ensure that only trusted identities can interact with your cloud resources.
Centralized IAM is critical for cloud security. Without it, organizations face inconsistent access controls, fragmented policies, and increased risk of unauthorized access. By enforcing centralized authentication and unified identity policies, you gain better visibility, consistent enforcement, and stronger protection against identity-based threats.
Keycloak
Keycloak is an open-source IAM solution that offers robust authentication and authorization features for modern applications and services. With Keycloak, you can integrate SSO, identity federation, and centralized user management across your cloud and on-premises systems.
Keycloak provides out-of-the-box support for multiple authentication protocols like OAuth 2.0, OpenID Connect, and SAML, making it a versatile solution for a variety of environments. It enables you to centralize identity management and ensure that user access policies are consistently enforced across your environment.
5. Secrets management — HashiCorp Vault
Secrets are digital authentication credentials, such as API, SSH, and encryption keys, that grant access to certain resources, systems, and/or data. Secrets can initiate communications between users and devices or machines and confirm they are trusted entities.
Secrets management involves a set of centralized tools, methods, and workflows that organizations use to securely store, retrieve, and manage their secrets or digital authentication credentials. It helps avoid the risks associated with hardcoded credentials, which can expose sensitive information–easy targets for attackers. By properly managing secrets, organizations can authenticate and verify identities before authorizing access, while keeping credentials secure—strengthening their overall IT security posture.
HashiCorp Vault
HashiCorp Vault is an open-source IAM tool that securely stores, manages, and controls access to secrets and encryption keys. It encrypts secrets at rest and tightly controls access through fine-grained policies and authentication methods.
Vault supports dynamic secrets by generating temporary credentials on demand to reduce exposure risks. It also offers automatic key rotation and revocation, which is an important identity security best practice. With support for API-driven workflows and integrations with cloud platforms, Vault ensures secrets remain protected across distributed and dynamic environments.
6. SIEM & log management — Wazuh
A security information and event management (SIEM) system is a centralized platform that collects, analyzes, and correlates security data from across an organization’s infrastructure. It aggregates logs, events, and alerts from servers, applications, network devices, and cloud services to provide real-time visibility into security incidents. SIEMs are critical for cloud security because they enable organizations to detect threats early, respond faster, and meet compliance requirements.
Wazuh
Wazuh is an open-source SIEM and extended detection and response (XDR) tool that provides threat detection, incident response, and compliance monitoring. It collects and correlates data from endpoints, cloud environments, and network devices to detect suspicious activity and security events.
With integrated log analysis, file integrity monitoring, and intrusion detection, Wazuh helps organizations spot anomalies, investigate incidents, and respond in real time. It also offers compliance auditing capabilities, which helps organizations meet regulations such as PCI DSS, GDPR, and HIPAA. Wazuh’s scalability and modular architecture make it a strong tool for managing security across cloud-native and hybrid environments.
7. Network security & visibility — Zeek
Network security and visibility are essential for detecting and preventing threats in cloud environments. As organizations adopt cloud-native architectures, their attack surfaces expand, which makes it harder to spot malicious activity. Deep network visibility allows you to monitor traffic flows, identify anomalies, and detect suspicious behavior in real time.
By monitoring network traffic, you can uncover stealthy threats, such as data exfiltration, lateral movement, and command-and-control (C2) communications. Having complete network visibility also makes a big difference when it comes to forensics and incident response. It gives you the context you need to investigate security incidents more effectively.
Zeek
Zeek is an open-source network traffic analysis tool that provides visibility into cloud and on-premises network activity. It passively monitors traffic, extracting detailed metadata such as connection logs, DNS requests, SSL certificates, and HTTP transactions.
Zeek’s extensible scripting language lets you create custom detection rules, making it great for spotting network anomalies and potential threats. It can identify suspicious patterns, command-and-control traffic, and policy violations, helping you spot malicious activity as it happens. With its rich metadata and flexible architecture, Zeek is a powerful tool for cloud network security and supplementing incident investigations with valuable insights.
8. Cloud penetration testing — Cloud Security Suite
Cloud penetration testing is a proactive security measure that simulates real-world attacks against cloud environments to identify vulnerabilities before malicious actors do. As organizations increasingly depend on cloud infrastructure, regular penetration testing has become crucial for identifying misconfigurations, insecure APIs, and exploitable vulnerabilities.
By running controlled penetration tests, you can validate cloud defenses, assess how well detection and response mechanisms work, and harden your cloud environments against future threats. Proactive testing also helps your organization meet compliance requirements and improve overall security resilience.
Cloud Security Suite
Cloud Security Suite is an open-source toolkit designed specifically for penetration testing in cloud environments. It offers a range of modules for testing the security posture of AWS, Azure, and GCP environments that help you uncover misconfigurations, weak access controls, and exploitable vulnerabilities.
The suite enables you to scan cloud assets, validate IAM policies, and assess storage and network security. Its modular design allows for custom testing scenarios that make it flexible and adaptable to different cloud infrastructures.
9. Continuous compliance — OpenSCAP
In cloud environments, regulatory compliance is an ongoing requirement for every organization. With ever-evolving frameworks like CIS, NIST, and GDPR, maintaining continuous compliance requires automated, real-time checks.
Continuous compliance ensures that misconfigurations, vulnerabilities, or deviations from security policies are detected and addressed before they become liabilities. By integrating automated compliance scanning into CI/CD pipelines and production environments, your organization can proactively demonstrate adherence to industry regulations and avoid costly penalties.
OpenSCAP
OpenSCAP is an open-source compliance scanning and vulnerability assessment tool that automates the evaluation of security policies. It uses the Security Content Automation Protocol (SCAP) standard maintained by NIST to assess cloud workloads, containers, and host systems against industry benchmarks. OpenSCAP generates detailed reports highlighting non-compliant configurations and provides remediation guidance to help you quickly address issues. By supporting widely recognized frameworks like CIS, NIST, and PCI-DSS, OpenSCAP helps streamline compliance efforts, reduce audit overhead, and strengthen an organization’s security posture.
Conclusion
The open-source cloud security tools we’ve explored offer tremendous value for organizations looking to safeguard their cloud-native environments. They are cost-effective, community-driven solutions to help security teams address vulnerabilities, detect threats, and maintain regulatory adherence. Leveraging these tools can significantly enhance an organization’s security posture and give teams the flexibility they need to customize their defenses.
While there are many reasons to use open source security tools, there is one important consideration. These tools require a dedicated effort to stay up-to-date with patches, maintenance, and community contributions. For organizations that need a more streamlined and scalable approach or don’t have the resources to dedicate to open source tool maintenance, a vendor-managed cloud security platform might be a better fit.
Sysdig Secure provides comprehensive security for cloud-native environments, offering a single integrated solution for threat detection, compliance monitoring, and incident response. With its powerful capabilities, it helps organizations manage security seamlessly across containers, Kubernetes, and cloud infrastructures.
To learn more about how Sysdig can enhance your cloud security posture, visit Sysdig Secure.