Brute force attack against user credentials Uses Authentication Normalization

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Id	a6c435a2-b1a0-466d-b730-9f8af69262e8
Rulename	Brute force attack against user credentials (Uses Authentication Normalization)
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
Severity	Medium
Tactics	CredentialAccess
Techniques	T1110
Kind	Scheduled
Query frequency	20m
Query period	20m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthBruteForce.yaml
Version	1.2.5
Arm template	a6c435a2-b1a0-466d-b730-9f8af69262e8.json

KQL

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])
      , ""
  )

YAML

severity: Medium
relevantTechniques:
- T1110
customDetails:
  ReportedBy: ReportedBy
  IpAddresses: IpAddresses
queryFrequency: 20m
kind: Scheduled
version: 1.2.5
metadata:
  support:
    tier: Community
  categories:
    domains:
    - Security - Others
    - Identity
  author:
    name: Ofer Shezaf
  source:
    kind: Community
name: Brute force attack against user credentials (Uses Authentication Normalization)
triggerOperator: gt
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)'  
queryPeriod: 20m
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])
        , ""
    )  
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: TargetUserName
    identifier: FullName
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
tactics:
- CredentialAccess
tags:
- Id: 28b42356-45af-40a6-a0b4-a554cdfd5d8a
  version: 1.0.0
- Schema: ASIMAuthentication
  SchemaVersion: 0.1.0
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthBruteForce.yaml
id: a6c435a2-b1a0-466d-b730-9f8af69262e8
requiredDataConnectors: []

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-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",
        "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"
    }
  ]
}