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_disabled
s3_bucket_encryption_enabled
iam_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