improper-bucket-sse: Improper Bucket Server-Side Encryption

id: improper-bucket-sse

info:
  name: Improper Bucket Server-Side Encryption
  author: ritikchaddha
  severity: medium
  description: |
    Determine the Server-Side Encryption (SSE) feature configuration available for the selected OSS bucket. For compliance, the SSEAlgorithm must be set to KMS.
  reference:
    - https://www.trendmicro.com/cloudoneconformity/knowledge-base/alibaba-cloud/AlibabaCloud-OSS/enable-sse-with-customer-managed-key.html
  metadata:
    max-request: 1
    verified: true
  tags: cloud,devops,aliyun,alibaba,aliyun-cloud-config,oss

variables:
  region: "cn-hangzhou"

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

self-contained: true

code:
  - engine:
      - sh
      - bash
    source: |
      ossutil ls -s --region $region

    extractors:
      - type: regex
        name: bucketname
        internal: true
        regex:
          - 'oss://([a-zA-Z0-9-]+)'

  - engine:
      - sh
      - bash
    source: |
      ossutil bucket-encryption --method get $bucket

    matchers:
      - type: regex
        regex:
          - 'SSEAlgorithm:\s?AES256'
          - 'StatusCode=404'

    extractors:
      - type: dsl
        dsl:
          - 'bucket + " Bucket SSEAlgorithm is not set to KMS"'
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