AWSCloudTrail - SSM document is publicly exposed

AWSCloudTrail
| where  EventName == "ModifyDocumentPermission" and isempty(ErrorCode) and isempty(ErrorMessage)
| where todynamic(parse_json(RequestParameters).["accountIdsToAdd"]) == '["all"]'
| 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]), "")  
| project TimeGenerated, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserAgent,UserIdentityUserName, SessionMfaAuthenticated, RecipientAccountId, AccountName, AccountUPNSuffix, SourceIpAddress, AWSRegion, EventSource, AdditionalEventData, RequestParameters, ResponseElements, UserIdentityArn

OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon%20Web%20Services/Analytic%20Rules/AWS_SSMPubliclyExposed.yaml
entityMappings:
- fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
  entityType: Account
- fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
  entityType: IP
relevantTechniques:
- T1526
triggerOperator: gt
queryPeriod: 1d
severity: Medium
query: |
  AWSCloudTrail
  | where  EventName == "ModifyDocumentPermission" and isempty(ErrorCode) and isempty(ErrorMessage)
  | where todynamic(parse_json(RequestParameters).["accountIdsToAdd"]) == '["all"]'
  | 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]), "")  
  | project TimeGenerated, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserAgent,UserIdentityUserName, SessionMfaAuthenticated, RecipientAccountId, AccountName, AccountUPNSuffix, SourceIpAddress, AWSRegion, EventSource, AdditionalEventData, RequestParameters, ResponseElements, UserIdentityArn
id: 75647b58-bcc8-4eb5-9658-46698d3fa153
triggerThreshold: 0
customDetails:
  AWSRegion: AWSRegion
  RequestParameters: RequestParameters
  UserAgent: UserAgent
  EventName: EventName
requiredDataConnectors:
- connectorId: AWS
  dataTypes:
  - AWSCloudTrail
queryFrequency: 1d
kind: Scheduled
status: Available
alertDetailsOverride:
  alertDisplayNameFormat: SSM document publicly exposed by {{AccountName}} in {{AWSRegion}}
  alertDescriptionFormat: User {{AccountName}} modified SSM document permissions to expose it publicly from {{SourceIpAddress}} in region {{AWSRegion}}.
version: 1.0.2
description: |
  Detects an AWS Systems Manager (SSM) document that has been made publicly accessible, which could lead to sensitive information exposure. Verify the document configurations and confirm the change was authorized.
tactics:
- Discovery
name: AWSCloudTrail - SSM document is publicly exposed

{
  "$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/75647b58-bcc8-4eb5-9658-46698d3fa153')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/75647b58-bcc8-4eb5-9658-46698d3fa153')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "User {{AccountName}} modified SSM document permissions to expose it publicly from {{SourceIpAddress}} in region {{AWSRegion}}.",
          "alertDisplayNameFormat": "SSM document publicly exposed by {{AccountName}} in {{AWSRegion}}"
        },
        "alertRuleTemplateName": "75647b58-bcc8-4eb5-9658-46698d3fa153",
        "customDetails": {
          "AWSRegion": "AWSRegion",
          "EventName": "EventName",
          "RequestParameters": "RequestParameters",
          "UserAgent": "UserAgent"
        },
        "description": "Detects an AWS Systems Manager (SSM) document that has been made publicly accessible, which could lead to sensitive information exposure. Verify the document configurations and confirm the change was authorized.\n",
        "displayName": "AWSCloudTrail - SSM document is 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%20Web%20Services/Analytic%20Rules/AWS_SSMPubliclyExposed.yaml",
        "query": "AWSCloudTrail\n| where  EventName == \"ModifyDocumentPermission\" and isempty(ErrorCode) and isempty(ErrorMessage)\n| where todynamic(parse_json(RequestParameters).[\"accountIdsToAdd\"]) == '[\"all\"]'\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| project TimeGenerated, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserAgent,UserIdentityUserName, SessionMfaAuthenticated, RecipientAccountId, AccountName, AccountUPNSuffix, SourceIpAddress, AWSRegion, EventSource, AdditionalEventData, RequestParameters, ResponseElements, UserIdentityArn\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Discovery"
        ],
        "techniques": [
          "T1526"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}