Security Hub

Security Hub gives a centralized dashboard of security events across data feeds from many different tools.

Custodian supports deep integration with security hub to support the following use cases.

  • post and update findings on any resource type to security hub See post-finding action

  • filtering resources on the basis of extant findings See finding filter

  • lambda execution mode triggered on ingestion of security hub findings mode: hub-finding

  • lambda execution mode as a custom action in the security hub ui. Note custodian security hub actions work against both findings and insights. mode: hub-action

Modes

Execute a policy lambda in response to security hub finding event or action.

This policy will provision a lambda and security hub custom action. The action can be invoked on a finding or insight result (collection of findings). The action name will have the resource type prefixed as custodian actions are resource specific.

policies:
  - name: remediate
    resource: aws.ec2
    mode:
      type: hub-action
      role: MyRole
    actions:
     - snapshot
     - type: set-instance-profile
       name: null
     - stop

This policy will provision a lambda that will process high alert findings from guard duty (note custodian also has support for guard duty events directly).

policies:
  - name: remediate
    resource: aws.iam
    mode:
      type: hub-finding
      role: MyRole
    filters:
      - type: event
        key: detail.findings[].ProductFields.aws/securityhub/ProductName
        value: GuardDuty
      - type: event
        key: detail.findings[].ProductFields.aws/securityhub/ProductName
        value: GuardDuty
    actions:
      - remove-keys

Note, for custodian we support additional resources in the finding via the Other resource, so these modes work for resources that security hub doesn’t natively support.

https://docs.aws.amazon.com/securityhub/latest/userguide/securityhub-cloudwatch-events.html

The Amazon Security Finding Format is documented at https://docs.aws.amazon.com/securityhub/latest/userguide/securityhub-findings-format.html

Mapping data in Cloud Custodian into the Amazon Security Finding Format (ASFF)

Cloud Custodian

ASFF Attribute

Rationale

derived from execution context: account_id

AwsAccountId

Direct

metadata.json policy.actions.compliance_status

Confidence

User supplied value in policy configuration

metadata.json policy.actions.confidence

Confidence

User supplied value in policy configuration

metadata.json policy.actions.criticality

Criticality

User supplied value in policy configuration

derived value: current_time aka Now

CreatedAt

Timestamp when the finding record was composed for the first time

metadata.json policy.actions.description

Description

User supplied value in policy configuration

metadata.json policy.name

GeneratorId

Policy is equivilent to a Rule

digest of region, account_id, policy contents, and Resource Arn/Id

Id

Enforces uniqueness by combinding policy attributes with resource attributes

metadata.json policy.resource_type

ProductFields.resource

Direct

fixed value: CloudCustodian

ProductFields.ProviderName

Name of project

derived value from executable: version

ProductFields.ProviderVersioN

Direct

fixed value: ACTIVE

RecordState

Always ACTIVE at Create/Update time

metadata.json policy.actions.recommendation

Recommendation.Text

User supplied value in policy configuration

metadata.json policy.actions.recommendation_url

Recommendation.Url

User supplied value in policy configuration

resources.json attributes

Resources.Details.${Type}.*

Direct Mapping from columns in Describe output

resources.json Arn

Resources.Id

Direct

resource.json Tags

Resources.Tags

Direct

metadata.json policy.resource_type

Resources.Type

Direct

Hardcoded Fixed Value: “2018-10-08”

SchemaVersion

Only Valid value

metadata.json policy.actions.severity_normalized

Severity.Normalized

User supplied value in policy configuration

metadata.json policy.name

Title

Primary Identifer

metadata.json policy.actions.types

Types

User supplied value in policy configuration

derived value: current_time aka Now

UpdatedAt

Timestamp when the finding record update is composed