Public Access of S3 Buckets via Policy

ID: s3-bucket-policy-public-access

Severity: critical

Author: princechaddha

Tags: cloud,devops,aws,amazon,s3,aws-cloud-config

Description

This template checks if Amazon S3 buckets are configured to prevent public access via bucket policies

YAML Source

id: s3-bucket-policy-public-access
info:
  name: Public Access of S3 Buckets via Policy
  author: princechaddha
  severity: critical
  description: |
    This template checks if Amazon S3 buckets are configured to prevent public access via bucket policies
  reference:
    - https://docs.aws.amazon.com/cli/latest/reference/s3api/get-bucket-policy.html
  metadata:
    max-request: 2
  tags: cloud,devops,aws,amazon,s3,aws-cloud-config

flow: |
  code(1)
  for(let bucketName of iterate(template.buckets)){
    set("bucket", bucketName)
    code(2)
  }

self-contained: true
code:
  - engine:
      - sh
      - bash
    source: |
      aws s3api list-buckets --query 'Buckets[*].Name'

    extractors:
      - type: json # type of the extractor
        internal: true
        name: buckets
        json:
          - '.[]'

  - engine:
      - sh
      - bash
    source: |
      aws s3api get-bucket-policy --bucket $bucket --query Policy --output text

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - '"Effect":"Allow"'

      - type: word
        part: body
        words:
          - '"Principal":"*"'
          - '"AWS":"*"'

    extractors:
      - type: dsl
        dsl:
          - '"The S3 bucket " + bucket +" is publicly accessible via Policy"'
# digest: 4a0a00473045022100c62712d0155b3a6ab8cad4c8d7a87284079288e840855539a4186055949e17f2022061849f7af633798a71f6769172339151da4f05799827c15cc680ee59bfbbf55d:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

$ nuclei -u "URL" -t "cloud/aws/s3/s3-bucket-policy-public-access.yaml"

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