RDS instance publicly exposed

AWSCloudTrail
| where  EventName in ("CreateDBInstance", "ModifyDBInstance") and isempty(ErrorCode) and isempty(ErrorMessage)
| where tostring(parse_json(RequestParameters).publiclyAccessible) == "true"
| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
| extend UserName = tostring(split(UserIdentityArn, '/')[-1])
| extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
| extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
  AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
| extend timestamp = TimeGenerated

relevantTechniques:
- T1537
triggerThreshold: 0
version: 1.0.2
triggerOperator: gt
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
name: RDS instance publicly exposed
query: |
  AWSCloudTrail
  | where  EventName in ("CreateDBInstance", "ModifyDBInstance") and isempty(ErrorCode) and isempty(ErrorMessage)
  | where tostring(parse_json(RequestParameters).publiclyAccessible) == "true"
  | extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
  | extend UserName = tostring(split(UserIdentityArn, '/')[-1])
  | extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
  | extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
    AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
  | extend timestamp = TimeGenerated  
severity: Medium
kind: Scheduled
status: Available
description: |
    'Detected publicly exposed RDS instance, which could lead to a leakage of sensitive data.'
queryFrequency: 1h
tactics:
- Exfiltration
queryPeriod: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_RDSInstancePubliclyExposed.yaml
id: 8f1630c2-2e45-4df2-be43-50fba90f601d
entityMappings:
- fieldMappings:
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
  - identifier: CloudAppAccountId
    columnName: RecipientAccountId
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: SourceIpAddress
  entityType: IP

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/8f1630c2-2e45-4df2-be43-50fba90f601d')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/8f1630c2-2e45-4df2-be43-50fba90f601d')]",
      "properties": {
        "alertRuleTemplateName": "8f1630c2-2e45-4df2-be43-50fba90f601d",
        "customDetails": null,
        "description": "'Detected publicly exposed RDS instance, which could lead to a leakage of sensitive data.'\n",
        "displayName": "RDS instance publicly exposed",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountUPNSuffix",
                "identifier": "UPNSuffix"
              },
              {
                "columnName": "RecipientAccountId",
                "identifier": "CloudAppAccountId"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SourceIpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_RDSInstancePubliclyExposed.yaml",
        "query": "AWSCloudTrail\n| where  EventName in (\"CreateDBInstance\", \"ModifyDBInstance\") and isempty(ErrorCode) and isempty(ErrorMessage)\n| where tostring(parse_json(RequestParameters).publiclyAccessible) == \"true\"\n| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)\n| extend UserName = tostring(split(UserIdentityArn, '/')[-1])\n| extend AccountName = case( UserIdentityPrincipalid == \"Anonymous\", \"Anonymous\", isempty(UserIdentityUserName), UserName, UserIdentityUserName)\n| extend AccountName = iif(AccountName contains \"@\", tostring(split(AccountName, '@', 0)[0]), AccountName),\n  AccountUPNSuffix = iif(AccountName contains \"@\", tostring(split(AccountName, '@', 1)[0]), \"\")\n| extend timestamp = TimeGenerated\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Exfiltration"
        ],
        "techniques": [
          "T1537"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}