SNS topic is publicly accessible

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Metadata

Id: 905f4741-f965-45c1-98db-f7a00a0e5c73

Cloud Provider: AWS

Platform: Ansible

Severity: High

Category: Access Control

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Description

SNS topic policies must not allow any principal (*). Making a topic public permits unauthorized publishing or subscription, which can lead to message injection, data exfiltration, or unintended triggering of downstream systems.

In Ansible tasks using the community.aws.sns_topic or sns_topic modules, check the policy property and flag any Statement with "Effect": "Allow" where Principal is the wildcard ("*") or contains "AWS": "*". Policy statements must instead specify explicit principals such as AWS account IDs, ARNs, or service principals. Statements that use a wildcard principal or are not limited to a specific account ID are flagged.

Secure configuration example for an Ansible task (explicit principal):

- name: create sns topic with restricted policy
  community.aws.sns_topic:
    name: my-topic
    policy:
      Version: "2012-10-17"
      Statement:
        - Sid: AllowSpecificAccount
          Effect: Allow
          Principal:
            AWS: "arn:aws:iam::123456789012:root"
          Action: "SNS:Publish"
          Resource: "arn:aws:sns:us-east-1:123456789012:my-topic"

Compliant Code Examples

- name: Create alarm SNS topic community
  community.aws.sns_topic:
    name: alarms
    state: present
    display_name: alarm SNS topic
    delivery_policy:
      http:
        defaultHealthyRetryPolicy:
          minDelayTarget: 2
          maxDelayTarget: 4
          numRetries: 3
          numMaxDelayRetries: 5
          backoffFunction: <linear|arithmetic|geometric|exponential>
        disableSubscriptionOverrides: true
        defaultThrottlePolicy:
          maxReceivesPerSecond: 10
    policy:
      Version: '2022-05-02'
      Statement:
      - Effect: Allow
        Action: Publish
        Principal: NotAll

- name: Create alarm SNS topic
  sns_topic:
    name: alarms
    state: present
    display_name: alarm SNS topic
    delivery_policy:
      http:
        defaultHealthyRetryPolicy:
          minDelayTarget: 2
          maxDelayTarget: 4
          numRetries: 3
          numMaxDelayRetries: 5
          backoffFunction: <linear|arithmetic|geometric|exponential>
        disableSubscriptionOverrides: true
        defaultThrottlePolicy:
          maxReceivesPerSecond: 10
    policy:
      Version: '2022-05-02'
      Statement:
      - Effect: Allow
        Action: Publish
        Principal: NotAll

# Principal "*" but limited to account ID via Condition - should NOT be flagged (is_access_limited_to_an_account_id)
- name: SNS topic with star principal but aws:SourceAccount condition
  community.aws.sns_topic:
    name: account-scoped-topic
    state: present
    policy:
      Version: '2012-10-17'
      Statement:
      - Effect: Allow
        Action: sns:Publish
        Principal: "*"
        Resource: "*"
        Condition:
          StringEquals:
            aws:SourceAccount: "123456789012"

Non-Compliant Code Examples

---
- name: Create alarm SNS topic community
  community.aws.sns_topic:
    name: "alarms"
    state: present
    display_name: "alarm SNS topic"
    delivery_policy:
      http:
        defaultHealthyRetryPolicy:
          minDelayTarget: 2
          maxDelayTarget: 4
          numRetries: 3
          numMaxDelayRetries: 5
          backoffFunction: "<linear|arithmetic|geometric|exponential>"
        disableSubscriptionOverrides: True
        defaultThrottlePolicy:
          maxReceivesPerSecond: 10
    subscriptions:
      - endpoint: "my_email_address@example.com"
        protocol: "email"
      - endpoint: "my_mobile_number"
        protocol: "sms"
    policy:
      Version: '2022-05-02'
      Statement:
        - Action: Publish
          Effect: Allow
          Principal: "*"
- name: Create alarm SNS topic
  sns_topic:
    name: "alarms"
    state: present
    display_name: "alarm SNS topic"
    delivery_policy:
      http:
        defaultHealthyRetryPolicy:
          minDelayTarget: 2
          maxDelayTarget: 4
          numRetries: 3
          numMaxDelayRetries: 5
          backoffFunction: "<linear|arithmetic|geometric|exponential>"
        disableSubscriptionOverrides: True
        defaultThrottlePolicy:
          maxReceivesPerSecond: 10
    subscriptions:
      - endpoint: "my_email_address@example.com"
        protocol: "email"
      - endpoint: "my_mobile_number"
        protocol: "sms"
    policy:
      Version: '2022-05-02'
      Statement:
        - Effect: Allow
          Action: Publish
          Principal: '*'