Detect Windows Allow Firewall Rule AdditionModification

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Id	056593d4-ca3b-47a7-be9d-d1d0884a1d36
Rulename	Detect Windows Allow Firewall Rule Addition/Modification
Description	This analytic rule detects any registry value creation or modification of Windows firewall registry keys to allow network traffic. This could be an indication of defense evasion by an adversary to allow network traffic to/from a compromised host.
Severity	Medium
Tactics	DefenseEvasion
Techniques	T1562
Required data connectors	CiscoSecureEndpoint CrowdStrikeFalconEndpointProtection MicrosoftThreatProtection SentinelOne TrendMicroApexOne TrendMicroApexOneAma VMwareCarbonBlack
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Malware%20Protection%20Essentials/Analytic%20Rules/WindowsAllowFirewallRuleAdded.yaml
Version	1.0.0
Arm template	056593d4-ca3b-47a7-be9d-d1d0884a1d36.json

KQL

// List of Windows Firewall registry keys to monitor
let firewallRegistryList = dynamic([
      'HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\SharedAccess\\Parameters\\FirewallPolicy\\RestrictedServices\\Static\\System',
      'HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\SharedAccess\\Parameters\\FirewallPolicy\\RestrictedServices\\Configurable\\System',
      'HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\SharedAccess\\Defaults\\FirewallPolicy\\FirewallRules',
      'HKEY_LOCAL_MACHINE\\SOFTWARE\\Policies\\Microsoft\\WindowsFirewall'
  ]);
_ASim_RegistryEvent
| where EventType in ('RegistryValueSet', 'RegistryKeyCreated') 
| where RegistryKey has_any (firewallRegistryList) and RegistryValueData has_all ('Action=Allow', 'Active=TRUE')
| project
    TimeGenerated,
    DvcHostname,
    ActorUsername,
    ActorUsernameType,
    ActingProcessId,
    ActingProcessName,
    ActingProcessCommandLine,
    RegistryKey,
    RegistryValue,
    RegistryValueType,
    RegistryValueData
| extend HostName = tostring(split(DvcHostname, '.')[0])
| extend DnsDomain = tostring(strcat_array(array_slice(split(DvcHostname, '.'), 1, -1), '.'))
| extend Username = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\')[1]), ActorUsername)
| extend NTDomain = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\')[0]), ActorUsername)
| extend Username = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[0]), Username)
| extend UPNSuffix = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[1]), '')
| extend RegHive = tostring(split(RegistryKey, '\\')[0]), RegKey = tostring(strcat_array(array_slice(split(RegistryKey, '\\'), 1, -1), '\\'))

YAML

status: Available
query: |
  // List of Windows Firewall registry keys to monitor
  let firewallRegistryList = dynamic([
        'HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\SharedAccess\\Parameters\\FirewallPolicy\\RestrictedServices\\Static\\System',
        'HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\SharedAccess\\Parameters\\FirewallPolicy\\RestrictedServices\\Configurable\\System',
        'HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\SharedAccess\\Defaults\\FirewallPolicy\\FirewallRules',
        'HKEY_LOCAL_MACHINE\\SOFTWARE\\Policies\\Microsoft\\WindowsFirewall'
    ]);
  _ASim_RegistryEvent
  | where EventType in ('RegistryValueSet', 'RegistryKeyCreated') 
  | where RegistryKey has_any (firewallRegistryList) and RegistryValueData has_all ('Action=Allow', 'Active=TRUE')
  | project
      TimeGenerated,
      DvcHostname,
      ActorUsername,
      ActorUsernameType,
      ActingProcessId,
      ActingProcessName,
      ActingProcessCommandLine,
      RegistryKey,
      RegistryValue,
      RegistryValueType,
      RegistryValueData
  | extend HostName = tostring(split(DvcHostname, '.')[0])
  | extend DnsDomain = tostring(strcat_array(array_slice(split(DvcHostname, '.'), 1, -1), '.'))
  | extend Username = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\')[1]), ActorUsername)
  | extend NTDomain = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\')[0]), ActorUsername)
  | extend Username = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[0]), Username)
  | extend UPNSuffix = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[1]), '')
  | extend RegHive = tostring(split(RegistryKey, '\\')[0]), RegKey = tostring(strcat_array(array_slice(split(RegistryKey, '\\'), 1, -1), '\\')) 
queryPeriod: 1h
relevantTechniques:
- T1562
entityMappings:
- entityType: Host
  fieldMappings:
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: DnsDomain
  - identifier: NTDomain
    columnName: NTDomain
- entityType: Account
  fieldMappings:
  - identifier: Name
    columnName: Username
  - identifier: UPNSuffix
    columnName: UPNSuffix
  - identifier: NTDomain
    columnName: NTDomain
- entityType: Process
  fieldMappings:
  - identifier: ProcessId
    columnName: ActingProcessId
  - identifier: CommandLine
    columnName: ActingProcessCommandLine
- entityType: RegistryKey
  fieldMappings:
  - identifier: Hive
    columnName: RegHive
  - identifier: Key
    columnName: RegKey
- entityType: RegistryValue
  fieldMappings:
  - identifier: Name
    columnName: RegistryValue
  - identifier: Value
    columnName: RegistryValueData
  - identifier: ValueType
    columnName: RegistryValueType
id: 056593d4-ca3b-47a7-be9d-d1d0884a1d36
requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: CrowdStrikeFalconEndpointProtection
- dataTypes:
  - SecurityAlert
  connectorId: MicrosoftThreatProtection
- dataTypes:
  - SentinelOne_CL
  connectorId: SentinelOne
- dataTypes:
  - CarbonBlackEvents_CL
  connectorId: VMwareCarbonBlack
- dataTypes:
  - CiscoSecureEndpoint_CL
  connectorId: CiscoSecureEndpoint
- dataTypes:
  - TMApexOneEvent
  connectorId: TrendMicroApexOne
- dataTypes:
  - TMApexOneEvent
  connectorId: TrendMicroApexOneAma
tactics:
- DefenseEvasion
triggerOperator: gt
eventGroupingSettings:
  aggregationKind: singleAlert
name: Detect Windows Allow Firewall Rule Addition/Modification
triggerThreshold: 0
severity: Medium
alertDetailsOverride:
  alertDescriptionFormat: An allow Firewall Rule {{RegistryValueData}} added at registry key {{RegKey}} by {{Username}}.
  alertDisplayNameFormat: Allow Firewall Rule {{RegistryValueData}} added at registry key {{RegKey}} on {{HostName}}
tags:
- SchemaVersion: 0.1.2
  Schema: _ASim_RegistryEvent
description: |
  This analytic rule detects any registry value creation or modification of Windows firewall registry keys to allow network traffic. This could be an indication of defense evasion by an adversary to allow network traffic to/from a compromised host.
version: 1.0.0
queryFrequency: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Malware%20Protection%20Essentials/Analytic%20Rules/WindowsAllowFirewallRuleAdded.yaml
kind: Scheduled

ARM

{
  "$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/056593d4-ca3b-47a7-be9d-d1d0884a1d36')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/056593d4-ca3b-47a7-be9d-d1d0884a1d36')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "An allow Firewall Rule {{RegistryValueData}} added at registry key {{RegKey}} by {{Username}}.",
          "alertDisplayNameFormat": "Allow Firewall Rule {{RegistryValueData}} added at registry key {{RegKey}} on {{HostName}}"
        },
        "alertRuleTemplateName": "056593d4-ca3b-47a7-be9d-d1d0884a1d36",
        "customDetails": null,
        "description": "This analytic rule detects any registry value creation or modification of Windows firewall registry keys to allow network traffic. This could be an indication of defense evasion by an adversary to allow network traffic to/from a compromised host.\n",
        "displayName": "Detect Windows Allow Firewall Rule Addition/Modification",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "DnsDomain",
                "identifier": "DnsDomain"
              },
              {
                "columnName": "NTDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Username",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              },
              {
                "columnName": "NTDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Process",
            "fieldMappings": [
              {
                "columnName": "ActingProcessId",
                "identifier": "ProcessId"
              },
              {
                "columnName": "ActingProcessCommandLine",
                "identifier": "CommandLine"
              }
            ]
          },
          {
            "entityType": "RegistryKey",
            "fieldMappings": [
              {
                "columnName": "RegHive",
                "identifier": "Hive"
              },
              {
                "columnName": "RegKey",
                "identifier": "Key"
              }
            ]
          },
          {
            "entityType": "RegistryValue",
            "fieldMappings": [
              {
                "columnName": "RegistryValue",
                "identifier": "Name"
              },
              {
                "columnName": "RegistryValueData",
                "identifier": "Value"
              },
              {
                "columnName": "RegistryValueType",
                "identifier": "ValueType"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "singleAlert"
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Malware%20Protection%20Essentials/Analytic%20Rules/WindowsAllowFirewallRuleAdded.yaml",
        "query": "// List of Windows Firewall registry keys to monitor\nlet firewallRegistryList = dynamic([\n      'HKEY_LOCAL_MACHINE\\\\SYSTEM\\\\CurrentControlSet\\\\Services\\\\SharedAccess\\\\Parameters\\\\FirewallPolicy\\\\RestrictedServices\\\\Static\\\\System',\n      'HKEY_LOCAL_MACHINE\\\\SYSTEM\\\\CurrentControlSet\\\\Services\\\\SharedAccess\\\\Parameters\\\\FirewallPolicy\\\\RestrictedServices\\\\Configurable\\\\System',\n      'HKEY_LOCAL_MACHINE\\\\SYSTEM\\\\CurrentControlSet\\\\Services\\\\SharedAccess\\\\Defaults\\\\FirewallPolicy\\\\FirewallRules',\n      'HKEY_LOCAL_MACHINE\\\\SOFTWARE\\\\Policies\\\\Microsoft\\\\WindowsFirewall'\n  ]);\n_ASim_RegistryEvent\n| where EventType in ('RegistryValueSet', 'RegistryKeyCreated') \n| where RegistryKey has_any (firewallRegistryList) and RegistryValueData has_all ('Action=Allow', 'Active=TRUE')\n| project\n    TimeGenerated,\n    DvcHostname,\n    ActorUsername,\n    ActorUsernameType,\n    ActingProcessId,\n    ActingProcessName,\n    ActingProcessCommandLine,\n    RegistryKey,\n    RegistryValue,\n    RegistryValueType,\n    RegistryValueData\n| extend HostName = tostring(split(DvcHostname, '.')[0])\n| extend DnsDomain = tostring(strcat_array(array_slice(split(DvcHostname, '.'), 1, -1), '.'))\n| extend Username = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\\\')[1]), ActorUsername)\n| extend NTDomain = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\\\')[0]), ActorUsername)\n| extend Username = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[0]), Username)\n| extend UPNSuffix = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[1]), '')\n| extend RegHive = tostring(split(RegistryKey, '\\\\')[0]), RegKey = tostring(strcat_array(array_slice(split(RegistryKey, '\\\\'), 1, -1), '\\\\')) \n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "tags": [
          {
            "Schema": "_ASim_RegistryEvent",
            "SchemaVersion": "0.1.2"
          }
        ],
        "techniques": [
          "T1562"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}