Prowler Review: Open Source Cloud Security That Automates Compliance

Managing multi-cloud security and compliance is a full-time job. Prowler is an open-source cloud security platform that automates hundreds of checks against AWS, Azure, GCP, Kubernetes, and more, producing actionable reports aligned with standards like CIS, NIST, GDPR, and PCI-DSS. It's trusted by thousands of organizations and has earned its reputation as the de facto open-source CSPM tool.

What is Prowler? An Open Source Cloud Security Platform

Prowler is a Python-based command-line tool and web application that scans your cloud environments for misconfigurations, excessive permissions, and compliance violations. It supports more than 10 cloud providers—including AWS (595 checks), Azure (167), GCP (102), Kubernetes, GitHub, and Oracle Cloud—and maps results to over 40 compliance frameworks. You can run it as a one-off audit, integrate it into CI/CD pipelines, or use the hosted Prowler Cloud interface for continuous monitoring.

Instead of writing custom scripts for every CIS benchmark or GDPR requirement, you run a single command and get a prioritized list of findings with remediation guidance. This saves time for small teams or solo DevOps engineers who need to demonstrate compliance without a dedicated security team.

Prowler operates by authenticating to your cloud provider using existing credentials (e.g., AWS IAM roles, Azure service principals, GCP service accounts). It then executes atomic checks for specific security configurations—like "S3 buckets should not be publicly accessible." The results are organized by provider, check, and compliance framework. You can output findings as JSON, CSV, HTML, or plain text for integration with other tools. The Prowler ThreatScore highlights the most critical findings first.

Getting Started with Prowler

Install Prowler via pip and run your first AWS scan:

pip install prowler
prowler aws

For Azure, use:

prowler azure --az-cli-login

To generate an HTML report with all findings:

prowler aws -M html

Prowler also runs in Docker, which is handy for CI/CD pipelines: docker run -v $(pwd):/output prowler/prowler aws -M json -o /output

Real-world example: Suppose you need to check compliance with the CIS AWS Foundations Benchmark. Run:

prowler aws --compliance cis_1.4_aws

This executes only the relevant checks and outputs a detailed report. To get a JSON summary of critical issues:

prowler aws --severity high --output-modes json | jq '.findings[] | select(.status == "FAIL") | {check_id, resource_id, severity}'

You can feed this JSON into your SIEM or incident management pipeline. For CI/CD integration, consider adding Prowler to GitHub Actions or Jenkins to fail builds on critical violations.

Pros and Cons

Pros

• Hundreds of pre-built checks across major cloud providers
• Supports 43 compliance frameworks for AWS alone
• Active open-source community (13k+ GitHub stars, frequent releases)
• Regular updates with new controls and frameworks
• Multiple output formats for easy integration
• Both CLI and web UI (Prowler Cloud) available

Cons

• Requires cloud IAM knowledge to configure credentials
• Large number of checks can be overwhelming without filtering
• Some checks are provider-specific
• Documentation can be dense for beginners
• Advanced features like Attack Paths need Neo4j setup

Prowler is fully open-source, but Prowler Cloud offers a managed version with additional features like continuous monitoring and alerting.

Alternatives to Prowler

• Checkov: Focuses on Infrastructure as Code scanning for Terraform, CloudFormation, and Kubernetes.
• Scout Suite: Multi-cloud security auditing tool with a clean web report, but less frequently updated.
• CloudSploit: Open-source cloud security scanner for AWS, Azure, and GCP, now part of Aqua Security.

Verdict: Should You Use Prowler?

Prowler is the best open-source option for multi-cloud compliance scanning if you need broad coverage and are comfortable with the CLI. It's ideal for security-conscious DevOps teams, compliance officers, and penetration testers who want a single tool for AWS, Azure, and GCP. Skip it if you only use one small cloud account and prefer a cloud-hosted SaaS solution—the setup overhead might not be worth it. For everyone else, Prowler is a must-have in your security toolkit.