Brute force attack against user credentials Uses Authentication Normalization

let failureCountThreshold = 10;
let successCountThreshold = 1;
// let authenticationWindow = 20m; // Implicit in the analytic rule query period 
imAuthentication
| where TargetUserType != "NonInteractive"
| summarize 
      StartTime = min(TimeGenerated), 
      EndTime = max(TimeGenerated), 
      IpAddresses = make_set (SrcDvcIpAddr, 100),
      ReportedBy = make_set (strcat (EventVendor, "/", EventProduct), 100),
      FailureCount = countif(EventResult=='Failure'),
      SuccessCount = countif(EventResult=='Success')
  by 
      TargetUserId, TargetUsername, TargetUserType 
| where FailureCount >= failureCountThreshold and SuccessCount >= successCountThreshold
| extend
      IpAddresses = strcat_array(IpAddresses, ", "), 
      ReportedBy = strcat_array(ReportedBy, ", ")
| extend
  Name = iif(
      TargetUsername contains "@"
          , tostring(split(TargetUsername, '@', 0)[0])
          , TargetUsername
      ),
  UPNSuffix = iif(
      TargetUsername contains "@"
      , tostring(split(TargetUsername, '@', 1)[0])
      , ""
  )

relevantTechniques:
- T1110
name: Brute force attack against user credentials (Uses Authentication Normalization)
requiredDataConnectors: []
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: TargetUserName
  - identifier: Name
    columnName: Name
  - identifier: UPNSuffix
    columnName: UPNSuffix
  entityType: Account
triggerThreshold: 0
id: a6c435a2-b1a0-466d-b730-9f8af69262e8
tactics:
- CredentialAccess
version: 1.2.5
customDetails:
  ReportedBy: ReportedBy
  IpAddresses: IpAddresses
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthBruteForce.yaml
queryPeriod: 20m
kind: Scheduled
tags:
- Id: 28b42356-45af-40a6-a0b4-a554cdfd5d8a
  version: 1.0.0
- Schema: ASIMAuthentication
  SchemaVersion: 0.1.0
metadata:
  categories:
    domains:
    - Security - Others
    - Identity
  author:
    name: Ofer Shezaf
  support:
    tier: Community
  source:
    kind: Community
queryFrequency: 20m
severity: Medium
description: |
  'Identifies evidence of brute force activity against a user based on multiple authentication failures and at least one successful authentication within a given time window.
  Note that the query does not enforce any sequence, and does not require the successful authentication to occur last.
  The default failure threshold is 10, success threshold is 1, and the default time window is 20 minutes.
  To use this analytics rule, make sure you have deployed the [ASIM normalization parsers](https://aka.ms/ASimAuthentication)'  
query: |
  let failureCountThreshold = 10;
  let successCountThreshold = 1;
  // let authenticationWindow = 20m; // Implicit in the analytic rule query period 
  imAuthentication
  | where TargetUserType != "NonInteractive"
  | summarize 
        StartTime = min(TimeGenerated), 
        EndTime = max(TimeGenerated), 
        IpAddresses = make_set (SrcDvcIpAddr, 100),
        ReportedBy = make_set (strcat (EventVendor, "/", EventProduct), 100),
        FailureCount = countif(EventResult=='Failure'),
        SuccessCount = countif(EventResult=='Success')
    by 
        TargetUserId, TargetUsername, TargetUserType 
  | where FailureCount >= failureCountThreshold and SuccessCount >= successCountThreshold
  | extend
        IpAddresses = strcat_array(IpAddresses, ", "), 
        ReportedBy = strcat_array(ReportedBy, ", ")
  | extend
    Name = iif(
        TargetUsername contains "@"
            , tostring(split(TargetUsername, '@', 0)[0])
            , TargetUsername
        ),
    UPNSuffix = iif(
        TargetUsername contains "@"
        , tostring(split(TargetUsername, '@', 1)[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": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/a6c435a2-b1a0-466d-b730-9f8af69262e8')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/a6c435a2-b1a0-466d-b730-9f8af69262e8')]",
      "properties": {
        "alertRuleTemplateName": "a6c435a2-b1a0-466d-b730-9f8af69262e8",
        "customDetails": {
          "IpAddresses": "IpAddresses",
          "ReportedBy": "ReportedBy"
        },
        "description": "'Identifies evidence of brute force activity against a user based on multiple authentication failures and at least one successful authentication within a given time window.\nNote that the query does not enforce any sequence, and does not require the successful authentication to occur last.\nThe default failure threshold is 10, success threshold is 1, and the default time window is 20 minutes.\nTo use this analytics rule, make sure you have deployed the [ASIM normalization parsers](https://aka.ms/ASimAuthentication)'\n",
        "displayName": "Brute force attack against user credentials (Uses Authentication Normalization)",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "TargetUserName",
                "identifier": "FullName"
              },
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthBruteForce.yaml",
        "query": "let failureCountThreshold = 10;\nlet successCountThreshold = 1;\n// let authenticationWindow = 20m; // Implicit in the analytic rule query period \nimAuthentication\n| where TargetUserType != \"NonInteractive\"\n| summarize \n      StartTime = min(TimeGenerated), \n      EndTime = max(TimeGenerated), \n      IpAddresses = make_set (SrcDvcIpAddr, 100),\n      ReportedBy = make_set (strcat (EventVendor, \"/\", EventProduct), 100),\n      FailureCount = countif(EventResult=='Failure'),\n      SuccessCount = countif(EventResult=='Success')\n  by \n      TargetUserId, TargetUsername, TargetUserType \n| where FailureCount >= failureCountThreshold and SuccessCount >= successCountThreshold\n| extend\n      IpAddresses = strcat_array(IpAddresses, \", \"), \n      ReportedBy = strcat_array(ReportedBy, \", \")\n| extend\n  Name = iif(\n      TargetUsername contains \"@\"\n          , tostring(split(TargetUsername, '@', 0)[0])\n          , TargetUsername\n      ),\n  UPNSuffix = iif(\n      TargetUsername contains \"@\"\n      , tostring(split(TargetUsername, '@', 1)[0])\n      , \"\"\n  )\n",
        "queryFrequency": "PT20M",
        "queryPeriod": "PT20M",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CredentialAccess"
        ],
        "tags": [
          {
            "Id": "28b42356-45af-40a6-a0b4-a554cdfd5d8a",
            "version": "1.0.0"
          },
          {
            "Schema": "ASIMAuthentication",
            "SchemaVersion": "0.1.0"
          }
        ],
        "techniques": [
          "T1110"
        ],
        "templateVersion": "1.2.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}