Microsoft Sentinel Analytic Rules
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Brute force attack against user credentials (Uses Authentication Normalization)

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Ida6c435a2-b1a0-466d-b730-9f8af69262e8
RulenameBrute force attack against user credentials (Uses Authentication Normalization)
DescriptionIdentifies 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
SeverityMedium
TacticsCredentialAccess
TechniquesT1110
KindScheduled
Query frequency20m
Query period20m
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthBruteForce.yaml
Version1.2.2
Arm templatea6c435a2-b1a0-466d-b730-9f8af69262e8.json
Deploy To Azure
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, ", ")
queryFrequency: 20m
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: TargetUsername
    identifier: FullName
severity: Medium
metadata:
  author:
    name: Ofer Shezaf
  source:
    kind: Community
  categories:
    domains:
    - Security - Others
    - Identity
  support:
    tier: Community
tags:
- version: 1.0.0
  Id: 28b42356-45af-40a6-a0b4-a554cdfd5d8a
- SchemaVersion: 0.1.0
  Schema: ASIMAuthentication
triggerThreshold: 0
relevantTechniques:
- T1110
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, ", ")  
id: a6c435a2-b1a0-466d-b730-9f8af69262e8
triggerOperator: gt
version: 1.2.2
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. 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
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthBruteForce.yaml
requiredDataConnectors: []
name: Brute force attack against user credentials (Uses Authentication Normalization)
tactics:
- CredentialAccess
kind: Scheduled
{
  "$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/a6c435a2-b1a0-466d-b730-9f8af69262e8')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/a6c435a2-b1a0-466d-b730-9f8af69262e8')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "Brute force attack against user credentials (Uses Authentication Normalization)",
        "description": "'Identifies evidence of brute force activity against a user based on multiple authentication failures \nand at least one successful authentication within a given time window. Note that the query does not enforce any sequence,\nand 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",
        "severity": "Medium",
        "enabled": true,
        "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",
        "queryFrequency": "PT20M",
        "queryPeriod": "PT20M",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CredentialAccess"
        ],
        "techniques": [
          "T1110"
        ],
        "alertRuleTemplateName": "a6c435a2-b1a0-466d-b730-9f8af69262e8",
        "customDetails": {
          "ReportedBy": "ReportedBy",
          "IpAddresses": "IpAddresses"
        },
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "TargetUsername"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthBruteForce.yaml",
        "tags": [
          {
            "version": "1.0.0",
            "Id": "28b42356-45af-40a6-a0b4-a554cdfd5d8a"
          },
          {
            "Schema": "ASIMAuthentication",
            "SchemaVersion": "0.1.0"
          }
        ],
        "templateVersion": "1.2.2"
      }
    }
  ]
}