Add AWS CloudFormation misconfiguration rule pack#241
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Six high-precision pattern-regex rules in scanner/rules/cloudformation.yml
covering raw CFN templates (YAML/JSON/.template), a gap next to the existing
Terraform-AWS coverage:
- cfn-iam-policy-star-star (CRITICAL): Action:* with Resource:* in one
statement, with statement-boundary tempering to avoid cross-statement FPs
- cfn-s3-bucket-public-acl (HIGH): AccessControl PublicRead/PublicReadWrite
windowed on Type: AWS::S3::Bucket
- cfn-security-group-open-world (HIGH): ingress open to 0.0.0.0/0 or ::/0;
default open egress does not fire
- cfn-rds-publicly-accessible (HIGH): PubliclyAccessible: true (CFN casing)
- cfn-storage-unencrypted (HIGH): StorageEncrypted: false or EBS volume
Encrypted: false
- cfn-secret-parameter-default (HIGH): secret-named Parameter with a literal
Default; {{resolve:...}} dynamic references pass
Every pattern is anchored on CFN-specific context (AWS:: type names,
PascalCase property names), and tests assert zero findings on Kubernetes
manifests, docker-compose files, and GitHub Actions workflows. 29 new tests
(positives, negatives, severities, e2e scans); repo self-scan stays clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EywwS2Du8pimW7xqRP3An3
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Summary
Adds
scanner/rules/cloudformation.yml— six high-precisionpattern-regexrules for raw AWS CloudFormation templates (.yaml/.yml/.json/.template). Terraform-AWS misconfigurations are already covered by external engines; raw CFN templates were a gap.cfn-iam-policy-star-starAction: *withResource: *in one IAM statement (full account admin)cfn-s3-bucket-public-aclAWS::S3::BucketwithAccessControl: PublicRead(Write)cfn-security-group-open-world0.0.0.0/0/::/0cfn-rds-publicly-accessiblePubliclyAccessible: true(CFN casing)cfn-storage-unencryptedStorageEncrypted: false/ EBS volumeEncrypted: falsecfn-secret-parameter-defaultDefaultvaluePrecision
AWS::resource type names, PascalCase property names) — the pack does not blanket-match all YAML.{{resolve:secretsmanager:...}}/ SSM dynamic references pass the secret-default rule; CDK camelCase (publiclyAccessible) and lowercase GitHub Actionsdefault:keys do not match.Testing
tests/test_cloudformation_rules.py: 29 tests — positives/negatives per rule, severity checks, e2e scans (misconfigured template fires all six; secure template, k8s, compose, and workflow fixtures stay clean). Secret-shaped fixtures are assembled at runtime.cfn-*findings; the new rule file and test file trigger no rules at all.🤖 Generated with Claude Code
https://claude.ai/code/session_01EywwS2Du8pimW7xqRP3An3