Potential Fodhelper UAC Bypass

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Id	56f3f35c-3aca-4437-a1fb-b7a84dc4af00
Rulename	Potential Fodhelper UAC Bypass
Description	This detection looks for the steps required to conduct a UAC bypass using Fodhelper.exe. By default this detection looks for the setting of the required registry keys and the invoking of the process within 1 hour - this can be tweaked as required.
Severity	Medium
Tactics	PrivilegeEscalation
Techniques	T1548.002
Required data connectors	SecurityEvents WindowsSecurityEvents
Kind	Scheduled
Query frequency	2h
Query period	2h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Analytic Rules/PotentialFodhelperUACBypass.yaml
Version	1.0.2
Arm template	56f3f35c-3aca-4437-a1fb-b7a84dc4af00.json

KQL

SecurityEvent
  | where EventID == 4657
  | parse ObjectName with "\\REGISTRY\\" KeyPrefix "\\" RegistryKey
  | project-reorder RegistryKey
  | where RegistryKey has "Software\\Classes\\ms-settings\\shell\\open\\command"
  | extend TimeKey = bin(TimeGenerated, 1h)
  | join (
  SecurityEvent
  | where EventID == 4688
  | where Process =~ "fodhelper.exe"
  | where ParentProcessName endswith "cmd.exe" or ParentProcessName endswith "powershell.exe" or ParentProcessName endswith "powershell_ise.exe"
  | extend TimeKey = bin(TimeGenerated, 1h)) on TimeKey, Computer
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | extend AccountName = tostring(split(TargetAccount, @'\')[1]), AccountNTDomain = tostring(split(TargetAccount, @'\')[0])

YAML

triggerOperator: gt
queryFrequency: 2h
description: |
    'This detection looks for the steps required to conduct a UAC bypass using Fodhelper.exe. By default this detection looks for the setting of the required registry keys and the invoking of the process within 1 hour - this can be tweaked as required.'
status: Available
kind: Scheduled
triggerThreshold: 0
requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsSecurityEvents
  dataTypes:
  - SecurityEvent
version: 1.0.2
queryPeriod: 2h
name: Potential Fodhelper UAC Bypass
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Analytic Rules/PotentialFodhelperUACBypass.yaml
id: 56f3f35c-3aca-4437-a1fb-b7a84dc4af00
tactics:
- PrivilegeEscalation
relevantTechniques:
- T1548.002
severity: Medium
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: Computer
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: HostNameDomain
  entityType: Host
- fieldMappings:
  - identifier: FullName
    columnName: TargetAccount
  - identifier: Name
    columnName: AccountName
  - identifier: NTDomain
    columnName: AccountNTDomain
  entityType: Account
query: |
  SecurityEvent
    | where EventID == 4657
    | parse ObjectName with "\\REGISTRY\\" KeyPrefix "\\" RegistryKey
    | project-reorder RegistryKey
    | where RegistryKey has "Software\\Classes\\ms-settings\\shell\\open\\command"
    | extend TimeKey = bin(TimeGenerated, 1h)
    | join (
    SecurityEvent
    | where EventID == 4688
    | where Process =~ "fodhelper.exe"
    | where ParentProcessName endswith "cmd.exe" or ParentProcessName endswith "powershell.exe" or ParentProcessName endswith "powershell_ise.exe"
    | extend TimeKey = bin(TimeGenerated, 1h)) on TimeKey, Computer
    | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
    | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
    | extend AccountName = tostring(split(TargetAccount, @'\')[1]), AccountNTDomain = tostring(split(TargetAccount, @'\')[0])

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/56f3f35c-3aca-4437-a1fb-b7a84dc4af00')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/56f3f35c-3aca-4437-a1fb-b7a84dc4af00')]",
      "properties": {
        "alertRuleTemplateName": "56f3f35c-3aca-4437-a1fb-b7a84dc4af00",
        "customDetails": null,
        "description": "'This detection looks for the steps required to conduct a UAC bypass using Fodhelper.exe. By default this detection looks for the setting of the required registry keys and the invoking of the process within 1 hour - this can be tweaked as required.'\n",
        "displayName": "Potential Fodhelper UAC Bypass",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "Computer",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "DnsDomain"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "TargetAccount",
                "identifier": "FullName"
              },
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountNTDomain",
                "identifier": "NTDomain"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Analytic Rules/PotentialFodhelperUACBypass.yaml",
        "query": "SecurityEvent\n  | where EventID == 4657\n  | parse ObjectName with \"\\\\REGISTRY\\\\\" KeyPrefix \"\\\\\" RegistryKey\n  | project-reorder RegistryKey\n  | where RegistryKey has \"Software\\\\Classes\\\\ms-settings\\\\shell\\\\open\\\\command\"\n  | extend TimeKey = bin(TimeGenerated, 1h)\n  | join (\n  SecurityEvent\n  | where EventID == 4688\n  | where Process =~ \"fodhelper.exe\"\n  | where ParentProcessName endswith \"cmd.exe\" or ParentProcessName endswith \"powershell.exe\" or ParentProcessName endswith \"powershell_ise.exe\"\n  | extend TimeKey = bin(TimeGenerated, 1h)) on TimeKey, Computer\n  | extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n  | extend AccountName = tostring(split(TargetAccount, @'\\')[1]), AccountNTDomain = tostring(split(TargetAccount, @'\\')[0])\n",
        "queryFrequency": "PT2H",
        "queryPeriod": "PT2H",
        "severity": "Medium",
        "status": "Available",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "PrivilegeEscalation"
        ],
        "techniques": [
          "T1548"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}