OSS Bucket Allows Put Action From All Principals

• Query id: fe286195-e75c-4359-bd58-00847c4f855a
• Query name: OSS Bucket Allows Put Action From All Principals
• Platform: Terraform
• Severity: High
• Category: Access Control
• URL: Github

Description

OSS Bucket should not allow put action 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' contains 'Put', for all Principals.
Documentation

Code samples

Code samples with security vulnerabilities

Postitive test num. 1 - tf file

resource "alicloud_oss_bucket" "bucket-policy4" {
  bucket = "bucket-4-policy"
  acl    = "private"

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

Postitive test num. 2 - tf file

resource "alicloud_oss_bucket" "bucket-policy5" {
  bucket = "bucket-5-policy"
  acl    = "private"

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

Negative test num. 2 - tf file

resource "alicloud_oss_bucket" "bucket-policy2" {
  bucket = "bucket-2-policy"
  acl    = "private"

  policy = <<POLICY
  {"Statement": [
    {
        "Action": [
            "oss:PutObjectAcl", "oss:PutObject"
        ],
        "Effect": "Allow",
        "Principal": [
            "20214760404935xxxx"
        ],
        "Resource": [
            "acs:oss:*:174649585760xxxx:examplebucket"
        ]
    }
  ],
   "Version":"1"}
  POLICY
}

Negative test num. 3 - tf file

resource "alicloud_oss_bucket" "bucket-policy3" {
  bucket = "bucket-3-policy"
  acl    = "private"

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