OSS Bucket Allows All Actions From All Principals

• Query id: ec62a32c-a297-41ca-a850-cab40b42094a
• Query name: OSS Bucket Allows All Actions From All Principals
• Platform: Terraform
• Severity: High
• Category: Access Control
• URL: Github

Description

OSS Buckets should not allow all actions (wildcard) from all principals, as to prevent leaking private information to the entire internet or allow unauthorized data tampering/deletion. This means the 'Effect' must not be 'Allow' when the 'Action' is *, for all Principals.
Documentation

Code samples

Code samples with security vulnerabilities

Postitive test num. 1 - tf file

resource "alicloud_oss_bucket" "bucket-policy1" {
  bucket = "bucket-1-policy"
  acl    = "private"

  policy = <<POLICY
  {"Statement": [
    {
        "Action": [
            "oss:*"
        ],
        "Effect": "Allow",
        "Principal": [
            "*"
        ],
        "Resource": [
            "acs:oss:*:174649585760xxxx:examplebucket"
        ]
    }
  ],
   "Version":"1"}
  POLICY
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "alicloud_oss_bucket" "bucket-policy1" {
  bucket = "bucket-1-policy"
  acl    = "private"

  policy = <<POLICY
  {"Statement": [
    {
        "Action": [
            "oss:*"
        ],
        "Effect": "Deny",
        "Principal": [
            "*"
        ],
        "Resource": [
            "acs:oss:*:174649585760xxxx:examplebucket"
        ]
    }
  ],
   "Version":"1"}
  POLICY
}

Negative test num. 2 - tf file

resource "alicloud_oss_bucket" "bucket-policy1" {
  bucket = "bucket-1-policy"
  acl    = "private"

  policy = <<POLICY
  {"Statement": [
    {
        "Action": [
            "oss:ListObjects"
        ],
        "Effect": "Allow",
        "Principal": [
            "*"
        ],
        "Resource": [
            "acs:oss:*:174649585760xxxx:examplebucket"
        ]
    }
  ],
   "Version":"1"}
  POLICY
}