CFRipper

CFRipper is a Library and CLI security analyzer for AWS CloudFormation templates. You can use CFRipper to prevent deploying insecure AWS resources into your Cloud environment. You can write your own compliance checks by adding new custom plugins.

Docs and more details available in https://cfripper.readthedocs.io/

CLI Usage

Normal execution

$ cfripper /tmp/root.yaml /tmp/root_bypass.json --format txt
Analysing /tmp/root.yaml...
Not adding CrossAccountTrustRule failure in rootRole because no AWS Account ID was found in the config.
Valid: False
Issues found:
 - FullWildcardPrincipalRule: rootRole should not allow full wildcard '*', or wildcard in account ID like 'arn:aws:iam::*:12345' at '*'
 - IAMRolesOverprivilegedRule: Role 'rootRole' contains an insecure permission '*' in policy 'root'
Analysing /tmp/root_bypass.json...
Valid: True

Using the "resolve" flag

$ cfripper /tmp/root.yaml /tmp/root_bypass.json --format txt --resolve
Analysing /tmp/root.yaml...
Not adding CrossAccountTrustRule failure in rootRole because no AWS Account ID was found in the config.
Valid: False
Issues found:
 - FullWildcardPrincipalRule: rootRole should not allow full wildcard '*', or wildcard in account ID like 'arn:aws:iam::*:12345' at '*'
 - IAMRolesOverprivilegedRule: Role 'rootRole' contains an insecure permission '*' in policy 'root'
Analysing /tmp/root_bypass.json...
Not adding CrossAccountTrustRule failure in rootRole because no AWS Account ID was found in the config.
Valid: False
Issues found:
 - IAMRolesOverprivilegedRule: Role 'rootRole' contains an insecure permission '*' in policy 'root'
Monitored issues found:
 - PartialWildcardPrincipalRule: rootRole contains an unknown principal: 123456789012
 - PartialWildcardPrincipalRule: rootRole should not allow wildcard, account-wide or root in resource-id like 'arn:aws:iam::12345:root' at 'arn:aws:iam::123456789012:root'

Using json format and output-folder argument

$ cfripper /tmp/root.yaml /tmp/root_bypass.json --format json --resolve --output-folder /tmp
Analysing /tmp/root.yaml...
Not adding CrossAccountTrustRule failure in rootRole because no AWS Account ID was found in the config.
Result saved in /tmp/root.yaml.cfripper.results.json
Analysing /tmp/root_bypass.json...
Not adding CrossAccountTrustRule failure in rootRole because no AWS Account ID was found in the config.
Result saved in /tmp/root_bypass.json.cfripper.results.json

Using rules config file

$ cfripper tests/test_templates/config/security_group_firehose_ips.json --rules-config-file cfripper/config/rule_configs/example_rules_config_for_cli.py
Analysing tests/test_templates/config/security_group_firehose_ips.json...
Valid: True

Using rules filters files

$ cfripper tests/test_templates/config/security_group_firehose_ips.json --rules-filters-folder cfripper/config/rule_configs/
example_rules_config_for_cli.py loaded
Analysing tests/test_templates/config/security_group_firehose_ips.json...
Valid: True

Exit Codes

"""
Analyse AWS Cloudformation templates passed by parameter.
Exit codes:
  - 0 = all templates valid and scanned successfully
  - 1 = error / issue in scanning at least one template
  - 2 = at least one template is not valid according to CFRipper (template scanned successfully)
  - 3 = unknown / unhandled exception in scanning the templates
"""

Development

Prerequisites

This project uses uv for dependency management. Install it with:

# macOS
brew install uv

# Linux/macOS
curl -LsSf https://astral.sh/uv/install.sh | sh

# Windows
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"

Setup

# Install development dependencies
make install-dev

# Run tests (lint + unit)
make test

# Run linter
make lint

# Format code
make format

# Update lock file after changing dependencies
make lock