DynamoDBはリージョンサービスの為、資格情報とインターネット接続環境があればどこからでも操作可能です。
監査等でデータイベントの記録を取得する要件もあると思いますので、CloudTrailでのログ記録の設定手順を記載します。
https://docs.aws.amazon.com/ja_jp/amazondynamodb/latest/developerguide/logging-using-cloudtrail.html

CloudTrailの証跡作成手順はAws/CloudTrail/証跡の作成を参照してください。

[
  {
    "name": "",
    "fieldSelectors": [
      {
        "field": "eventCategory",
        "equals": [
          "Data"
        ]
      },
      {
        "field": "resources.type",
        "equals": [
          "AWS::DynamoDB::Table"
        ]
      }
    ]
  }
]

[
  {
    "name": "",
    "fieldSelectors": [
      {
        "field": "eventCategory",
        "equals": [
          "Data"
        ]
      },
      {
        "field": "resources.type",
        "equals": [
          "AWS::DynamoDB::Table"
        ]
      },
      {
        "field": "resources.ARN",
        "equals": [
          "arn:aws:dynamodb:ap-northeast-1:{アカウントID}:table/{Table名}"
        ]
      }
    ]
  }
]

例では、[Scan][GetItem][PutItem][DeleteItem]を対象としています。

[
  {
    "name": "",
    "fieldSelectors": [
      {
        "field": "eventCategory",
        "equals": [
          "Data"
        ]
      },
      {
        "field": "resources.type",
        "equals": [
          "AWS::DynamoDB::Table"
        ]
      },
      {
        "field": "eventName",
        "equals": [
          "DeleteItem",
          "Scan",
          "GetItem",
          "PutItem"
        ]
      }
    ]
  }
]

{
  "Records": [
    {
      "eventVersion": "1.08",
      "userIdentity": {
        "type": "IAMUser",
        "principalId": "AIXCEWSFXSWQDVHCOX32D",
        "arn": "arn:aws:iam::{アカウントID}:user/{ユーザー名}",
        "accountId": "{アカウントID}",
        "accessKeyId": "{アクセスキー}",
        "userName": "{ユーザー名}",
        "sessionContext": {
          "attributes": {
            "creationDate": "2021-05-23T03:28:58Z",
            "mfaAuthenticated": "false"
          }
        }
      },
      "eventTime": "2021-05-23T04:08:14Z",
      "eventSource": "dynamodb.amazonaws.com",
      "eventName": "DeleteItem",
      "awsRegion": "ap-northeast-1",
      "sourceIPAddress": "{IPアドレス}",
      "userAgent": "aws-internal/3 aws-sdk-java/1.11.1005 Linux/5.4.109-57.183.amzn2int.x86_64 OpenJDK_64-Bit_Server_VM/25.292-b10 java/1.8.0_292 vendor/Oracle_Corporation cfg/retry-mode/legacy",
      "requestParameters": {
        "tableName": "{テーブル名}",
        "key": {
          "SensorID": "tokyo",
          "DeviceID": "001"
        }
      },
      "responseElements": null,
      "requestID": "QBRJP4PRL7VHE3UVGD8CIK10DNVV4KQNSO5AEMVJF66Q9ASUAAJG",
      "eventID": "6b9c78ad-5564-4a9b-aaa1-fae09259f0fb",
      "readOnly": false,
      "resources": [
        {
          "accountId": "{アカウントID}",
          "type": "AWS::DynamoDB::Table",
          "ARN": "arn:aws:dynamodb:ap-northeast-1:{アカウントID}:table/{テーブル名}"
        }
      ],
      "eventType": "AwsApiCall",
      "apiVersion": "2012-08-10",
      "managementEvent": false,
      "recipientAccountId": "{アカウントID}",
      "eventCategory": "Data"
    }
  ]
}