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Id6a2e2ff4-5568-475e-bef2-b95f12b9367b
RulenamePotential Password Spray Attack (Uses Authentication Normalization)
DescriptionThis query searches for failed attempts to log in from more than 15 various users within a 5 minute timeframe from the same source. This is a potential indication of a password spray attack

To use this analytics rule, make sure you have deployed the ASIM normalization parsers
SeverityMedium
TacticsCredentialAccess
TechniquesT1110
KindScheduled
Query frequency1h
Query period1h
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthPasswordSpray.yaml
Version1.1.3
Arm template6a2e2ff4-5568-475e-bef2-b95f12b9367b.json
Deploy To Azure
let FailureThreshold = 15;
imAuthentication
| where EventType== 'Logon' and  EventResult== 'Failure'
// reason: creds 
| where EventResultDetails in ('No such user or password', 'Incorrect password')
| summarize UserCount=dcount(TargetUserId), Vendors=make_set(EventVendor), Products=make_set(EventVendor)
  , Users = make_set(TargetUserId,100) 
    by SrcDvcIpAddr, SrcGeoCountry, bin(TimeGenerated, 5m)
| where UserCount > FailureThreshold
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthPasswordSpray.yaml
triggerOperator: gt
metadata:
  support:
    tier: Community
  categories:
    domains:
    - Security - Others
    - Identity
  author:
    name: Ofer Shezaf
  source:
    kind: Community
triggerThreshold: 0
id: 6a2e2ff4-5568-475e-bef2-b95f12b9367b
kind: Scheduled
relevantTechniques:
- T1110
version: 1.1.3
tactics:
- CredentialAccess
queryPeriod: 1h
queryFrequency: 1h
severity: Medium
name: Potential Password Spray Attack (Uses Authentication Normalization)
requiredDataConnectors: []
tags:
- version: 1.0.0
  Id: e27dd7e5-4367-4c40-a2b7-fcd7e7a8a508
- SchemaVersion: 0.1.0
  Schema: ASIMAuthentication
description: |
  'This query searches for failed attempts to log in from more than 15 various users within a 5 minute timeframe from the same source. This is a potential indication of a password spray attack
   To use this analytics rule, make sure you have deployed the [ASIM normalization parsers](https://aka.ms/ASimAuthentication)'
entityMappings:
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SrcDvcIpAddr
query: |
  let FailureThreshold = 15;
  imAuthentication
  | where EventType== 'Logon' and  EventResult== 'Failure'
  // reason: creds 
  | where EventResultDetails in ('No such user or password', 'Incorrect password')
  | summarize UserCount=dcount(TargetUserId), Vendors=make_set(EventVendor), Products=make_set(EventVendor)
    , Users = make_set(TargetUserId,100) 
      by SrcDvcIpAddr, SrcGeoCountry, bin(TimeGenerated, 5m)
  | where UserCount > FailureThreshold
{
  "$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/6a2e2ff4-5568-475e-bef2-b95f12b9367b')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/6a2e2ff4-5568-475e-bef2-b95f12b9367b')]",
      "properties": {
        "alertRuleTemplateName": "6a2e2ff4-5568-475e-bef2-b95f12b9367b",
        "customDetails": null,
        "description": "'This query searches for failed attempts to log in from more than 15 various users within a 5 minute timeframe from the same source. This is a potential indication of a password spray attack\n To use this analytics rule, make sure you have deployed the [ASIM normalization parsers](https://aka.ms/ASimAuthentication)'\n",
        "displayName": "Potential Password Spray Attack (Uses Authentication Normalization)",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcDvcIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimAuthentication/imAuthPasswordSpray.yaml",
        "query": "let FailureThreshold = 15;\nimAuthentication\n| where EventType== 'Logon' and  EventResult== 'Failure'\n// reason: creds \n| where EventResultDetails in ('No such user or password', 'Incorrect password')\n| summarize UserCount=dcount(TargetUserId), Vendors=make_set(EventVendor), Products=make_set(EventVendor)\n  , Users = make_set(TargetUserId,100) \n    by SrcDvcIpAddr, SrcGeoCountry, bin(TimeGenerated, 5m)\n| where UserCount > FailureThreshold\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CredentialAccess"
        ],
        "tags": [
          {
            "Id": "e27dd7e5-4367-4c40-a2b7-fcd7e7a8a508",
            "version": "1.0.0"
          },
          {
            "Schema": "ASIMAuthentication",
            "SchemaVersion": "0.1.0"
          }
        ],
        "techniques": [
          "T1110"
        ],
        "templateVersion": "1.1.3",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}