monocdk-nag 0.2.1

Check CDK applications for best practices using a combination on available rule packs.

cdk-nag

Language	cdk-nag	monocdk-nag
Python
TypeScript

Check CDK applications or CloudFormation templates for best practices using a combination of available rule packs. Inspired by cfn_nag

Available Packs

See RULES for more information on all the available packs.

1. AWS Solutions
2. HIPAA Security
3. NIST 800-53 rev 4
4. NIST 800-53 rev 5
5. PCI DSS 3.2.1

Usage

cdk

# Example automatically generated from non-compiling source. May contain errors.
from aws_cdk.core import App, Aspects
from ...lib.cdk_test_stack import CdkTestStack
from cdk_nag import AwsSolutionsChecks

app = App()
CdkTestStack(app, "CdkNagDemo")
# Simple rule informational messages
Aspects.of(app).add(AwsSolutionsChecks())

monocdk

# Example automatically generated from non-compiling source. May contain errors.
from monocdk import App, Aspects
from ...lib.my_stack import CdkTestStack
from monocdk_nag import AwsSolutionsChecks

app = App()
CdkTestStack(app, "CdkNagDemo")
# Simple rule informational messages
Aspects.of(app).add(AwsSolutionsChecks())

Suppressing a Rule

Example 1) Default Construct

# Example automatically generated from non-compiling source. May contain errors.
from aws_cdk.aws_ec2 import SecurityGroup, Vpc, Peer, Port
from aws_cdk.core import Construct, Stack, StackProps
from cdk_nag import NagSuppressions

class CdkTestStack(Stack):
    def __init__(self, scope, id, *, description=None, env=None, stackName=None, tags=None, synthesizer=None, terminationProtection=None, analyticsReporting=None):
        super().__init__(scope, id, description=description, env=env, stackName=stackName, tags=tags, synthesizer=synthesizer, terminationProtection=terminationProtection, analyticsReporting=analyticsReporting)
        test = SecurityGroup(self, "test",
            vpc=Vpc(self, "vpc")
        )
        test.add_ingress_rule(Peer.any_ipv4(), Port.all_traffic())
        NagSuppressions.add_resource_suppressions(test, [id="AwsSolutions-EC23", reason="lorem ipsum"
        ])

Example 2) Child Constructs

# Example automatically generated from non-compiling source. May contain errors.
from aws_cdk.aws_iam import User, PolicyStatement
from aws_cdk.core import Construct, Stack, StackProps
from cdk_nag import NagSuppressions

class CdkTestStack(Stack):
    def __init__(self, scope, id, *, description=None, env=None, stackName=None, tags=None, synthesizer=None, terminationProtection=None, analyticsReporting=None):
        super().__init__(scope, id, description=description, env=env, stackName=stackName, tags=tags, synthesizer=synthesizer, terminationProtection=terminationProtection, analyticsReporting=analyticsReporting)
        user = User(self, "rUser")
        user.add_to_policy(
            PolicyStatement(
                actions=["s3:PutObject"],
                resources=["arn:aws:s3:::bucket_name/*"]
            ))
        # Enable adding suppressions to child constructs
        NagSuppressions.add_resource_suppressions(user, [{"id": "AwsSolutions-IAM5", "reason": "lorem ipsum"}], True)

Example 3) Stack Level

# Example automatically generated from non-compiling source. May contain errors.
from aws_cdk.core import App, Aspects
from ...lib.cdk_test_stack import CdkTestStack
from cdk_nag import AwsSolutionsChecks, NagSuppressions

app = App()
stack = CdkTestStack(app, "CdkNagDemo")
Aspects.of(app).add(AwsSolutionsChecks())
NagSuppressions.add_stack_suppressions(stack, [id="AwsSolutions-EC23", reason="lorem ipsum"
])

Example 4) Construct path

If you received the following error on synth/deploy

[Error at /StackName/Custom::CDKBucketDeployment8675309/ServiceRole/Resource] AwsSolutions-IAM4: The IAM user, role, or group uses AWS managed policies

# Example automatically generated from non-compiling source. May contain errors.
from aws_cdk.aws_s3 import Bucket
from aws_cdk.aws_s3_deployment import BucketDeployment
from cdk_nag import NagSuppressions
from aws_cdk.core import Construct, Stack, StackProps

class CdkTestStack(Stack):
    def __init__(self, scope, id, *, description=None, env=None, stackName=None, tags=None, synthesizer=None, terminationProtection=None, analyticsReporting=None):
        super().__init__(scope, id, description=description, env=env, stackName=stackName, tags=tags, synthesizer=synthesizer, terminationProtection=terminationProtection, analyticsReporting=analyticsReporting)
        BucketDeployment(self, "rDeployment",
            sources=[],
            destination_bucket=Bucket.from_bucket_name(self, "rBucket", "foo")
        )
        NagSuppressions.add_resource_suppressions_by_path(self, "/StackName/Custom::CDKBucketDeployment8675309/ServiceRole/Resource", [id="AwsSolutions-IAM4", reason="at least 10 characters"])

Rules and Property Overrides

In some cases L2 Constructs do not have a native option to remediate an issue and must be fixed via Raw Overrides. Since raw overrides take place after template synthesis these fixes are not caught by the cdk_nag. In this case you should remediate the issue and suppress the issue like in the following example.

Example) Property Overrides

# Example automatically generated from non-compiling source. May contain errors.
from aws_cdk.aws_ec2 import Instance, InstanceType, InstanceClass, MachineImage, Vpc, CfnInstance
from aws_cdk.core import Construct, Stack, StackProps
from cdk_nag import NagSuppressions

class CdkTestStack(Stack):
    def __init__(self, scope, id, *, description=None, env=None, stackName=None, tags=None, synthesizer=None, terminationProtection=None, analyticsReporting=None):
        super().__init__(scope, id, description=description, env=env, stackName=stackName, tags=tags, synthesizer=synthesizer, terminationProtection=terminationProtection, analyticsReporting=analyticsReporting)
        instance = Instance(self, "rInstance",
            vpc=Vpc(self, "rVpc"),
            instance_type=InstanceType(InstanceClass.T3),
            machine_image=MachineImage.latest_amazon_linux()
        )
        cfn_ins = instance.node.default_child
        cfn_ins.add_property_override("DisableApiTermination", True)
        NagSuppressions.add_resource_suppressions(instance, [
            id="AwsSolutions-EC29",
            reason="Remediated through property override."

        ])

Using on CloudFormation templates

You can use cdk-nag on existing CloudFormation templates by using the cloudformation-include module.

Example) CloudFormation template with suppression

Sample CloudFormation template with suppression

{
  "Resources": {
    "rBucket": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "BucketName": "some-bucket-name"
      },
      "Metadata": {
        "cdk_nag": {
          "rules_to_suppress": [
            {
              "id": "AwsSolutions-S1",
              "reason": "at least 10 characters"
            }
          ]
        }
      }
    }
  }
}

Sample App

# Example automatically generated from non-compiling source. May contain errors.
from aws_cdk.core import App, Aspects
from ...lib.cdk_test_stack import CdkTestStack
from cdk_nag import AwsSolutionsChecks

app = App()
CdkTestStack(app, "CdkNagDemo")
Aspects.of(app).add(AwsSolutionsChecks())

Sample Stack with imported template

# Example automatically generated from non-compiling source. May contain errors.
from aws_cdk.cloudformation_include import CfnInclude
from cdk_nag import NagSuppressions
from aws_cdk.core import Construct, Stack, StackProps

class CdkTestStack(Stack):
    def __init__(self, scope, id, *, description=None, env=None, stackName=None, tags=None, synthesizer=None, terminationProtection=None, analyticsReporting=None):
        super().__init__(scope, id, description=description, env=env, stackName=stackName, tags=tags, synthesizer=synthesizer, terminationProtection=terminationProtection, analyticsReporting=analyticsReporting)
        CfnInclude(self, "Template",
            template_file="my-template.json"
        )
        # Add any additional suppressions
        NagSuppressions.add_resource_suppressions_by_path(self, "/CdkNagDemo/Template/rBucket", [
            id="AwsSolutions-S2",
            reason="at least 10 characters"

        ])

Contributing

See CONTRIBUTING for more information.

License

This project is licensed under the Apache-2.0 License.