Checkov is a static code analysis tool that scans your Infrastructure as Code (IaC) files for security misconfigurations.
Let’s see it in action. Imagine you have a Terraform file that defines an AWS S3 bucket:
resource "aws_s3_bucket" "example" {
bucket = "my-insecure-bucket"
acl = "public-read" # This is a major security risk!
versioning {
enabled = false # Not enabling versioning can lead to data loss
}
logging {
# Logging is not configured, so we can't audit access
}
}
When you run Checkov against this file, it will immediately flag the acl = "public-read" setting.
checkov -d .
Output would look something like this:
_
/ \ ___ ___ ___ _ __ _ _ ___ ___ ___ _ __ __ _ _ __ ___ ___ ___ ___
/ _ \ / __|/ _ \ / _ \| '_ \ | | | | / __|/ _ \ / _ \| '_ \ / _` || '__/ _ \ / __|/ _ \ / __|
/ ___ \ | (__| (_) | (_) | | | | | |_| | | (__| (_) | (_) | | | | | (_| || | | __/ | (__| (_) | (__
/_/ \_\ \___|\___/ \___/|_| |_| \__, | \___|\___/ \___/|_| |_| \__,_||_| \___| \___|\___/ \___|
|___/
[INFO] Scanning file: main.tf
[WARNING] S3 Bucket acl is set to public-read. This is a security risk.
[WARNING] S3 Bucket versioning is not enabled. This can lead to data loss.
[INFO] S3 Bucket logging is not configured. This can hinder auditing.
Checkov works by parsing your IaC files (like Terraform, CloudFormation, Kubernetes YAML, etc.) and comparing the declared resources and their configurations against a continuously updated library of known security best practices and compliance standards. It understands the structure and syntax of these languages, allowing it to interpret the intent behind your code.
The core problem Checkov solves is the inherent difficulty in manually verifying the security posture of infrastructure defined in code. As infrastructure grows in complexity and teams iterate rapidly, it’s easy for security misconfigurations to slip through the cracks. Checkov automates this crucial security step, integrating directly into the development workflow.
Internally, Checkov uses a combination of Abstract Syntax Trees (AST) for parsing and a rule engine to evaluate configurations against its policy database. Each rule in Checkov is designed to identify a specific type of misconfiguration. For example, a rule for S3 buckets might look for the acl attribute being set to public-read or public-read-write. If found, it generates a warning or error.
The levers you control with Checkov are primarily through its configuration and the policies you choose to enforce. You can:
- Specify the directory or files to scan:
checkov -d .orcheckov -f main.tf - Filter by framework:
checkov --framework terraform - Use specific check IDs:
checkov -c CKV_AWS_18(This specific ID checks for public S3 buckets.) - Enable or disable specific checks: You can create custom
.checkov.yamlfiles to tailor policies. - Integrate with CI/CD pipelines: This is where Checkov provides the most value, catching issues before they reach production.
- Enforce compliance standards: Checkov supports various standards like CIS Benchmarks, NIST, PCI DSS, etc.
One of the most powerful, yet often overlooked, aspects of Checkov is its ability to understand context. It doesn’t just look at individual resource attributes in isolation. For instance, it can correlate a security group rule with the resources it protects and determine if overly permissive access is granted to sensitive services. This contextual understanding allows it to catch more complex, multi-resource misconfigurations that simple pattern matching would miss.
When you run Checkov, it returns a list of found issues, including the check ID, the severity, the resource affected, and a detailed explanation of the misconfiguration and how to fix it. This makes remediation straightforward.
The next step after integrating Checkov into your workflow is often exploring its capabilities for custom policy creation to enforce organization-specific security standards.