Check Structure
prowler/providers/{provider}/services/{service}/{check_name}/
├── __init__.py
├── {check_name}.py
└── {check_name}.metadata.json
Step-by-Step Creation Process
1. Prerequisites
- Verify check doesn't exist: Search
prowler/providers/{provider}/services/{service}/ - Ensure provider and service exist - create them first if not
- Confirm service has required methods - may need to add/modify service methods to get data
2. Create Check Files
mkdir -p prowler/providers/{provider}/services/{service}/{check_name} touch prowler/providers/{provider}/services/{service}/{check_name}/__init__.py touch prowler/providers/{provider}/services/{service}/{check_name}/{check_name}.py touch prowler/providers/{provider}/services/{service}/{check_name}/{check_name}.metadata.json
3. Implement Check Logic
from prowler.lib.check.models import Check, Check_Report_{Provider} from prowler.providers.{provider}.services.{service}.{service}_client import {service}_client class {check_name}(Check): """Ensure that {resource} meets {security_requirement}.""" def execute(self) -> list[Check_Report_{Provider}]: """Execute the check logic. Returns: A list of reports containing the result of the check. """ findings = [] for resource in {service}_client.{resources}: report = Check_Report_{Provider}(metadata=self.metadata(), resource=resource) report.status = "PASS" if resource.is_compliant else "FAIL" report.status_extended = f"Resource {resource.name} compliance status." findings.append(report) return findings
4. Create Metadata File
See complete schema below and assets/ folder for complete templates.
For detailed field documentation, see references/metadata-docs.md.
5. Verify Check Detection
poetry run python prowler-cli.py {provider} --list-checks | grep {check_name}
6. Run Check Locally
poetry run python prowler-cli.py {provider} --log-level ERROR --verbose --check {check_name}
7. Create Tests
See prowler-test-sdk skill for test patterns (PASS, FAIL, no resources, error handling).
Check Naming Convention
{service}_{resource}_{security_control}
Examples:
ec2_instance_public_ip_disableds3_bucket_encryption_enablediam_user_mfa_enabled
Metadata Schema (COMPLETE)
{ "Provider": "aws", "CheckID": "{check_name}", "CheckTitle": "Human-readable title", "CheckType": [ "Software and Configuration Checks/AWS Security Best Practices", "Software and Configuration Checks/Industry and Regulatory Standards/AWS Foundational Security Best Practices" ], "ServiceName": "{service}", "SubServiceName": "", "ResourceIdTemplate": "", "Severity": "low|medium|high|critical", "ResourceType": "AwsEc2Instance|Other", "ResourceGroup": "security|compute|storage|network", "Description": "**Bold resource name**. Detailed explanation of what this check evaluates and why it matters.", "Risk": "What happens if non-compliant. Explain attack vectors, data exposure risks, compliance impact.", "RelatedUrl": "", "AdditionalURLs": [ "https://docs.aws.amazon.com/..." ], "Remediation": { "Code": { "CLI": "aws {service} {command} --option value", "NativeIaC": "```yaml\nResources:\n Resource:\n Type: AWS::{Service}::{Resource}\n Properties:\n Key: value # This line fixes the issue\n```", "Other": "1. Console steps\n2. Step by step", "Terraform": "```hcl\nresource \"aws_{service}_{resource}\" \"example\" {\n key = \"value\" # This line fixes the issue\n}\n```" }, "Recommendation": { "Text": "Detailed recommendation for remediation.", "Url": "https://hub.prowler.com/check/{check_name}" } }, "Categories": [ "identity-access", "encryption", "logging", "forensics-ready", "internet-exposed", "trust-boundaries" ], "DependsOn": [], "RelatedTo": [], "Notes": "" }
Required Fields
| Field | Description |
|---|---|
Provider | Provider name: aws, azure, gcp, kubernetes, github, m365 |
CheckID | Must match class name and folder name |
CheckTitle | Human-readable title |
Severity | low, medium, high, critical |
ServiceName | Service being checked |
Description | What the check evaluates |
Risk | Security impact of non-compliance |
Remediation.Code.CLI | CLI fix command |
Remediation.Recommendation.Text | How to fix |
Severity Guidelines
| Severity | When to Use |
|---|---|
critical | Direct data exposure, RCE, privilege escalation |
high | Significant security risk, compliance violation |
medium | Defense-in-depth, best practice |
low | Informational, minor hardening |
Check Report Statuses
| Status | When to Use |
|---|---|
PASS | Resource is compliant |
FAIL | Resource is non-compliant |
MANUAL | Requires human verification |
Common Patterns
AWS Check with Regional Resources
from prowler.lib.check.models import Check, Check_Report_AWS from prowler.providers.aws.services.s3.s3_client import s3_client class s3_bucket_encryption_enabled(Check): def execute(self) -> list[Check_Report_AWS]: findings = [] for bucket in s3_client.buckets.values(): report = Check_Report_AWS(metadata=self.metadata(), resource=bucket) if bucket.encryption: report.status = "PASS" report.status_extended = f"S3 bucket {bucket.name} has encryption enabled." else: report.status = "FAIL" report.status_extended = f"S3 bucket {bucket.name} does not have encryption enabled." findings.append(report) return findings
Check with Multiple Conditions
from prowler.lib.check.models import Check, Check_Report_AWS from prowler.providers.aws.services.ec2.ec2_client import ec2_client class ec2_instance_hardened(Check): def execute(self) -> list[Check_Report_AWS]: findings = [] for instance in ec2_client.instances: report = Check_Report_AWS(metadata=self.metadata(), resource=instance) issues = [] if instance.public_ip: issues.append("has public IP") if not instance.metadata_options.http_tokens == "required": issues.append("IMDSv2 not enforced") if issues: report.status = "FAIL" report.status_extended = f"Instance {instance.id} {', '.join(issues)}." else: report.status = "PASS" report.status_extended = f"Instance {instance.id} is properly hardened." findings.append(report) return findings
Commands
# Verify detection poetry run python prowler-cli.py {provider} --list-checks | grep {check_name} # Run check poetry run python prowler-cli.py {provider} --log-level ERROR --verbose --check {check_name} # Run with specific profile/credentials poetry run python prowler-cli.py aws --profile myprofile --check {check_name} # Run multiple checks poetry run python prowler-cli.py {provider} --check {check1} {check2} {check3}
Resources
- Templates: See assets/ for complete check and metadata templates (AWS, Azure, GCP)
- Documentation: See references/metadata-docs.md for official Prowler Developer Guide links