Microsoft Sentinel Analytic Rules
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S3 bucket access point publicly exposed

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Idb7a44e0d-ae4c-4fb2-be1b-aa0e45f2327b
RulenameS3 bucket access point publicly exposed
DescriptionDetected S3 bucket publicly exposed via access point, which could lead to sensitive information leakage to the public. Verify the S3 object configurations.
SeverityMedium
TacticsExfiltration
TechniquesT1537
Required data connectorsAWS
KindScheduled
Query frequency1h
Query period1h
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_S3BucketAccessPointExposed.yaml
Version1.0.0
Arm templateb7a44e0d-ae4c-4fb2-be1b-aa0e45f2327b.json
Deploy To Azure
AWSCloudTrail
| where EventName == "PutAccessPointPolicy" and isempty(ErrorCode) and isempty(ErrorMessage)
| extend Statement = parse_json(tostring((parse_json(RequestParameters).PutAccessPointPolicyRequest.Policy))).Statement
| mvexpand Statement
| extend Action = parse_json(Statement).Action , Effect = tostring(parse_json(Statement).Effect), Resource = tostring(parse_json(Statement).Resource), Condition = tostring(parse_json(Statement).Condition), Principal_aws = tostring(parse_json(Statement).Principal.AWS), Principal = tostring(parse_json(Statement).Principal)
| extend Action = tostring(Action)
| where Effect =~ "Allow" and (Principal_aws == "*" or Principal == "*") and isempty(Condition)
| distinct TimeGenerated, EventName, SourceIpAddress, UserIdentityArn, UserIdentityUserName
| extend UserIdentityUserName = iff(isnotempty(UserIdentityUserName), UserIdentityUserName, tostring(split(UserIdentityArn,'/')[-1]))
| extend timestamp = TimeGenerated, IPCustomEntity = SourceIpAddress, AccountCustomEntity = UserIdentityUserName
queryPeriod: 1h
version: 1.0.0
relevantTechniques:
- T1537
queryFrequency: 1h
kind: Scheduled
name: S3 bucket access point publicly exposed
id: b7a44e0d-ae4c-4fb2-be1b-aa0e45f2327b
entityMappings:
- fieldMappings:
  - columnName: AccountCustomEntity
    identifier: FullName
  entityType: Account
- fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
  entityType: IP
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_S3BucketAccessPointExposed.yaml
severity: Medium
query: |
  AWSCloudTrail
  | where EventName == "PutAccessPointPolicy" and isempty(ErrorCode) and isempty(ErrorMessage)
  | extend Statement = parse_json(tostring((parse_json(RequestParameters).PutAccessPointPolicyRequest.Policy))).Statement
  | mvexpand Statement
  | extend Action = parse_json(Statement).Action , Effect = tostring(parse_json(Statement).Effect), Resource = tostring(parse_json(Statement).Resource), Condition = tostring(parse_json(Statement).Condition), Principal_aws = tostring(parse_json(Statement).Principal.AWS), Principal = tostring(parse_json(Statement).Principal)
  | extend Action = tostring(Action)
  | where Effect =~ "Allow" and (Principal_aws == "*" or Principal == "*") and isempty(Condition)
  | distinct TimeGenerated, EventName, SourceIpAddress, UserIdentityArn, UserIdentityUserName
  | extend UserIdentityUserName = iff(isnotempty(UserIdentityUserName), UserIdentityUserName, tostring(split(UserIdentityArn,'/')[-1]))
  | extend timestamp = TimeGenerated, IPCustomEntity = SourceIpAddress, AccountCustomEntity = UserIdentityUserName  
tactics:
- Exfiltration
description: |
    'Detected S3 bucket publicly exposed via access point, which could lead to sensitive information leakage to the public. Verify the S3 object configurations.'
requiredDataConnectors:
- connectorId: AWS
  dataTypes:
  - AWSCloudTrail
status: Available
triggerThreshold: 0
triggerOperator: gt
{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/b7a44e0d-ae4c-4fb2-be1b-aa0e45f2327b')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/b7a44e0d-ae4c-4fb2-be1b-aa0e45f2327b')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "S3 bucket access point publicly exposed",
        "description": "'Detected S3 bucket publicly exposed via access point, which could lead to sensitive information leakage to the public. Verify the S3 object configurations.'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "AWSCloudTrail\n| where EventName == \"PutAccessPointPolicy\" and isempty(ErrorCode) and isempty(ErrorMessage)\n| extend Statement = parse_json(tostring((parse_json(RequestParameters).PutAccessPointPolicyRequest.Policy))).Statement\n| mvexpand Statement\n| extend Action = parse_json(Statement).Action , Effect = tostring(parse_json(Statement).Effect), Resource = tostring(parse_json(Statement).Resource), Condition = tostring(parse_json(Statement).Condition), Principal_aws = tostring(parse_json(Statement).Principal.AWS), Principal = tostring(parse_json(Statement).Principal)\n| extend Action = tostring(Action)\n| where Effect =~ \"Allow\" and (Principal_aws == \"*\" or Principal == \"*\") and isempty(Condition)\n| distinct TimeGenerated, EventName, SourceIpAddress, UserIdentityArn, UserIdentityUserName\n| extend UserIdentityUserName = iff(isnotempty(UserIdentityUserName), UserIdentityUserName, tostring(split(UserIdentityArn,'/')[-1]))\n| extend timestamp = TimeGenerated, IPCustomEntity = SourceIpAddress, AccountCustomEntity = UserIdentityUserName\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Exfiltration"
        ],
        "techniques": [
          "T1537"
        ],
        "alertRuleTemplateName": "b7a44e0d-ae4c-4fb2-be1b-aa0e45f2327b",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "AccountCustomEntity"
              }
            ],
            "entityType": "Account"
          },
          {
            "fieldMappings": [
              {
                "identifier": "Address",
                "columnName": "IPCustomEntity"
              }
            ],
            "entityType": "IP"
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_S3BucketAccessPointExposed.yaml",
        "status": "Available",
        "templateVersion": "1.0.0"
      }
    }
  ]
}