Conditional Access Policy Modified by New User

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Id	25a7f951-54b7-4cf5-9862-ebc04306c590
Rulename	Conditional Access Policy Modified by New User
Description	Detects a Conditional Access Policy being modified by a user who has not modified a policy in the last 14 days. A threat actor may try to modify policies to weaken the security controls in place. Investigate any change to ensure they are approved. Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-infrastructure#conditional-access
Severity	Medium
Tactics	DefenseEvasion
Techniques	T1078.004
Required data connectors	AzureActiveDirectory
Kind	Scheduled
Query frequency	1d
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ConditionalAccessPolicyModifiedbyNewUser.yaml
Version	1.0.2
Arm template	25a7f951-54b7-4cf5-9862-ebc04306c590.json

KQL

let known_users = (AuditLogs
  | where TimeGenerated between(ago(14d)..ago(1d))
  | where OperationName has "conditional access policy"
  | where Result =~ "success"
  | extend userPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
  | summarize by userPrincipalName);
  AuditLogs
  | where TimeGenerated > ago(1d)
  | where OperationName has "conditional access policy"
  | where Result =~ "success"
  | extend userPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
  | extend CAPolicyName = tostring(TargetResources[0].displayName)
  | extend ipAddress = tostring(parse_json(tostring(InitiatedBy.user)).ipAddress)
  | where userPrincipalName !in (known_users)
  | extend NewPolicyValues = TargetResources[0].modifiedProperties[0].newValue
  | extend OldPolicyValues = TargetResources[0].modifiedProperties[0].oldValue
  | project-reorder TimeGenerated, OperationName, CAPolicyName, userPrincipalName, ipAddress, NewPolicyValues, OldPolicyValues

YAML

id: 25a7f951-54b7-4cf5-9862-ebc04306c590
queryFrequency: 1d
version: 1.0.2
requiredDataConnectors:
- connectorId: AzureActiveDirectory
  dataTypes:
  - AuditLogs
entityMappings:
- fieldMappings:
  - columnName: userPrincipalName
    identifier: FullName
  entityType: Account
- fieldMappings:
  - columnName: ipAddress
    identifier: Address
  entityType: IP
kind: Scheduled
queryPeriod: 14d
severity: Medium
query: |
  let known_users = (AuditLogs
    | where TimeGenerated between(ago(14d)..ago(1d))
    | where OperationName has "conditional access policy"
    | where Result =~ "success"
    | extend userPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
    | summarize by userPrincipalName);
    AuditLogs
    | where TimeGenerated > ago(1d)
    | where OperationName has "conditional access policy"
    | where Result =~ "success"
    | extend userPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
    | extend CAPolicyName = tostring(TargetResources[0].displayName)
    | extend ipAddress = tostring(parse_json(tostring(InitiatedBy.user)).ipAddress)
    | where userPrincipalName !in (known_users)
    | extend NewPolicyValues = TargetResources[0].modifiedProperties[0].newValue
    | extend OldPolicyValues = TargetResources[0].modifiedProperties[0].oldValue
    | project-reorder TimeGenerated, OperationName, CAPolicyName, userPrincipalName, ipAddress, NewPolicyValues, OldPolicyValues  
metadata:
  categories:
    domains:
    - Security - Others
  author:
    name: Pete Bryan
  support:
    tier: Community
  source:
    kind: Community
triggerOperator: gt
tags:
- AADSecOpsGuide
description: |
  'Detects a Conditional Access Policy being modified by a user who has not modified a policy in the last 14 days.
    A threat actor may try to modify policies to weaken the security controls in place.
    Investigate any change to ensure they are approved.
    Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-infrastructure#conditional-access'  
triggerThreshold: 0
name: Conditional Access Policy Modified by New User
relevantTechniques:
- T1078.004
tactics:
- DefenseEvasion
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ConditionalAccessPolicyModifiedbyNewUser.yaml

ARM

{
  "$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/25a7f951-54b7-4cf5-9862-ebc04306c590')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/25a7f951-54b7-4cf5-9862-ebc04306c590')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "Conditional Access Policy Modified by New User",
        "description": "'Detects a Conditional Access Policy being modified by a user who has not modified a policy in the last 14 days.\n  A threat actor may try to modify policies to weaken the security controls in place.\n  Investigate any change to ensure they are approved.\n  Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-infrastructure#conditional-access'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let known_users = (AuditLogs\n  | where TimeGenerated between(ago(14d)..ago(1d))\n  | where OperationName has \"conditional access policy\"\n  | where Result =~ \"success\"\n  | extend userPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)\n  | summarize by userPrincipalName);\n  AuditLogs\n  | where TimeGenerated > ago(1d)\n  | where OperationName has \"conditional access policy\"\n  | where Result =~ \"success\"\n  | extend userPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)\n  | extend CAPolicyName = tostring(TargetResources[0].displayName)\n  | extend ipAddress = tostring(parse_json(tostring(InitiatedBy.user)).ipAddress)\n  | where userPrincipalName !in (known_users)\n  | extend NewPolicyValues = TargetResources[0].modifiedProperties[0].newValue\n  | extend OldPolicyValues = TargetResources[0].modifiedProperties[0].oldValue\n  | project-reorder TimeGenerated, OperationName, CAPolicyName, userPrincipalName, ipAddress, NewPolicyValues, OldPolicyValues\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P14D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1078.004"
        ],
        "alertRuleTemplateName": "25a7f951-54b7-4cf5-9862-ebc04306c590",
        "customDetails": null,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "userPrincipalName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "identifier": "Address",
                "columnName": "ipAddress"
              }
            ]
          }
        ],
        "tags": [
          "AADSecOpsGuide"
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ConditionalAccessPolicyModifiedbyNewUser.yaml",
        "templateVersion": "1.0.2"
      }
    }
  ]
}