Microsoft Sentinel Analytic Rules
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Rare application consent

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Id83ba3057-9ea3-4759-bf6a-933f2e5bc7ee
RulenameRare application consent
DescriptionThis will alert when the “Consent to application” operation occurs by a user that has not done this operation before or rarely does this.

This could indicate that permissions to access the listed Azure App were provided to a malicious actor.

Consent to application, Add service principal and Add OAuth2PermissionGrant should typically be rare events.

This may help detect the Oauth2 attack that can be initiated by this publicly available tool - https://github.com/fireeye/PwnAuth

For further information on AuditLogs please see https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities.
SeverityMedium
TacticsPersistence
PrivilegeEscalation
TechniquesT1136
T1068
Required data connectorsAzureActiveDirectory
KindScheduled
Query frequency1d
Query period7d
Trigger threshold3
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/RareApplicationConsent.yaml
Version1.1.5
Arm template83ba3057-9ea3-4759-bf6a-933f2e5bc7ee.json
Deploy To Azure
let current = 1d;
let auditLookback = 7d;
// Setting threshold to 3 as a default, change as needed.
// Any operation that has been initiated by a user or app more than 3 times in the past 7 days will be excluded
let threshold = 3;
// Gather initial data from lookback period, excluding current, adjust current to more than a single day if no results
let AuditTrail = AuditLogs | where TimeGenerated >= ago(auditLookback) and TimeGenerated < ago(current)
// 2 other operations that can be part of malicious activity in this situation are
// "Add OAuth2PermissionGrant" and "Add service principal", extend the filter below to capture these too
| where OperationName has "Consent to application"
| extend InitiatedBy = iff(isnotempty(tostring(InitiatedBy.user.userPrincipalName)),
          tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))
| mv-apply TargetResource = TargetResources on 
  (
      where TargetResource.type =~ "ServicePrincipal"
      | extend TargetResourceName = tolower(tostring(TargetResource.displayName))
  )
| summarize max(TimeGenerated), OperationCount = count() by OperationName, InitiatedBy, TargetResourceName
// only including operations initiated by a user or app that is above the threshold so we produce only rare and has not occurred in last 7 days
| where OperationCount > threshold;
// Gather current period of audit data
let RecentConsent = AuditLogs | where TimeGenerated >= ago(current)
| where OperationName has "Consent to application"
| extend IpAddress = case(
              isnotempty(tostring(InitiatedBy.user.ipAddress)) and tostring(InitiatedBy.user.ipAddress) != 'null', tostring(InitiatedBy.user.ipAddress),
              isnotempty(tostring(InitiatedBy.app.ipAddress)) and tostring(InitiatedBy.app.ipAddress) != 'null', tostring(InitiatedBy.app.ipAddress),
              'Not Available')
| extend InitiatedBy = iff(isnotempty(tostring(InitiatedBy.user.userPrincipalName)),
                          tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))
| mv-apply TargetResource = TargetResources on 
  (
      where TargetResource.type =~ "ServicePrincipal"
      | extend TargetResourceName = tolower(tostring(TargetResource.displayName)),
               props = TargetResource.modifiedProperties
  )
| parse props with * "ConsentType: " ConsentType "]" *
| mv-apply AdditionalDetail = AdditionalDetails on 
  (
      where AdditionalDetail.key =~ "User-Agent"
      | extend UserAgent = tostring(AdditionalDetail.value)
  )
| project TimeGenerated, InitiatedBy, IpAddress, TargetResourceName, Category, OperationName, ConsentType, UserAgent, CorrelationId, Type;
// Exclude previously seen audit activity for "Consent to application" that was seen in the lookback period
// First for rare InitiatedBy
let RareConsentBy = RecentConsent | join kind= leftanti AuditTrail on OperationName, InitiatedBy
| extend Reason = "Previously unseen user consenting";
// Second for rare TargetResourceName
let RareConsentApp = RecentConsent | join kind= leftanti AuditTrail on OperationName, TargetResourceName
| extend Reason = "Previously unseen app granted consent";
RareConsentBy | union RareConsentApp
| summarize Reason = make_set(Reason,100) by TimeGenerated, InitiatedBy, IpAddress, TargetResourceName, Category, OperationName, ConsentType, UserAgent, CorrelationId, Type
| extend timestamp = TimeGenerated, Name = tolower(tostring(split(InitiatedBy,'@',0)[0])), UPNSuffix = tolower(tostring(split(InitiatedBy,'@',1)[0]))

triggerOperator: gt
queryFrequency: 1d
description: |
  'This will alert when the "Consent to application" operation occurs by a user that has not done this operation before or rarely does this.
  This could indicate that permissions to access the listed Azure App were provided to a malicious actor.
  Consent to application, Add service principal and Add OAuth2PermissionGrant should typically be rare events.
  This may help detect the Oauth2 attack that can be initiated by this publicly available tool - https://github.com/fireeye/PwnAuth
  For further information on AuditLogs please see https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities.'  
status: Available
kind: Scheduled
triggerThreshold: 3
requiredDataConnectors:
- connectorId: AzureActiveDirectory
  dataTypes:
  - AuditLogs
version: 1.1.5
queryPeriod: 7d
name: Rare application consent
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/RareApplicationConsent.yaml
id: 83ba3057-9ea3-4759-bf6a-933f2e5bc7ee
tactics:
- Persistence
- PrivilegeEscalation
relevantTechniques:
- T1136
- T1068
severity: Medium
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: InitiatedBy
  - identifier: Name
    columnName: Name
  - identifier: UPNSuffix
    columnName: UPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: Name
    columnName: TargetResourceName
  entityType: CloudApplication
- fieldMappings:
  - identifier: Address
    columnName: IpAddress
  entityType: IP
query: |
  let current = 1d;
  let auditLookback = 7d;
  // Setting threshold to 3 as a default, change as needed.
  // Any operation that has been initiated by a user or app more than 3 times in the past 7 days will be excluded
  let threshold = 3;
  // Gather initial data from lookback period, excluding current, adjust current to more than a single day if no results
  let AuditTrail = AuditLogs | where TimeGenerated >= ago(auditLookback) and TimeGenerated < ago(current)
  // 2 other operations that can be part of malicious activity in this situation are
  // "Add OAuth2PermissionGrant" and "Add service principal", extend the filter below to capture these too
  | where OperationName has "Consent to application"
  | extend InitiatedBy = iff(isnotempty(tostring(InitiatedBy.user.userPrincipalName)),
            tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))
  | mv-apply TargetResource = TargetResources on 
    (
        where TargetResource.type =~ "ServicePrincipal"
        | extend TargetResourceName = tolower(tostring(TargetResource.displayName))
    )
  | summarize max(TimeGenerated), OperationCount = count() by OperationName, InitiatedBy, TargetResourceName
  // only including operations initiated by a user or app that is above the threshold so we produce only rare and has not occurred in last 7 days
  | where OperationCount > threshold;
  // Gather current period of audit data
  let RecentConsent = AuditLogs | where TimeGenerated >= ago(current)
  | where OperationName has "Consent to application"
  | extend IpAddress = case(
                isnotempty(tostring(InitiatedBy.user.ipAddress)) and tostring(InitiatedBy.user.ipAddress) != 'null', tostring(InitiatedBy.user.ipAddress),
                isnotempty(tostring(InitiatedBy.app.ipAddress)) and tostring(InitiatedBy.app.ipAddress) != 'null', tostring(InitiatedBy.app.ipAddress),
                'Not Available')
  | extend InitiatedBy = iff(isnotempty(tostring(InitiatedBy.user.userPrincipalName)),
                            tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))
  | mv-apply TargetResource = TargetResources on 
    (
        where TargetResource.type =~ "ServicePrincipal"
        | extend TargetResourceName = tolower(tostring(TargetResource.displayName)),
                 props = TargetResource.modifiedProperties
    )
  | parse props with * "ConsentType: " ConsentType "]" *
  | mv-apply AdditionalDetail = AdditionalDetails on 
    (
        where AdditionalDetail.key =~ "User-Agent"
        | extend UserAgent = tostring(AdditionalDetail.value)
    )
  | project TimeGenerated, InitiatedBy, IpAddress, TargetResourceName, Category, OperationName, ConsentType, UserAgent, CorrelationId, Type;
  // Exclude previously seen audit activity for "Consent to application" that was seen in the lookback period
  // First for rare InitiatedBy
  let RareConsentBy = RecentConsent | join kind= leftanti AuditTrail on OperationName, InitiatedBy
  | extend Reason = "Previously unseen user consenting";
  // Second for rare TargetResourceName
  let RareConsentApp = RecentConsent | join kind= leftanti AuditTrail on OperationName, TargetResourceName
  | extend Reason = "Previously unseen app granted consent";
  RareConsentBy | union RareConsentApp
  | summarize Reason = make_set(Reason,100) by TimeGenerated, InitiatedBy, IpAddress, TargetResourceName, Category, OperationName, ConsentType, UserAgent, CorrelationId, Type
  | extend timestamp = TimeGenerated, Name = tolower(tostring(split(InitiatedBy,'@',0)[0])), UPNSuffix = tolower(tostring(split(InitiatedBy,'@',1)[0]))  

{
  "$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/83ba3057-9ea3-4759-bf6a-933f2e5bc7ee')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/83ba3057-9ea3-4759-bf6a-933f2e5bc7ee')]",
      "properties": {
        "alertRuleTemplateName": "83ba3057-9ea3-4759-bf6a-933f2e5bc7ee",
        "customDetails": null,
        "description": "'This will alert when the \"Consent to application\" operation occurs by a user that has not done this operation before or rarely does this.\nThis could indicate that permissions to access the listed Azure App were provided to a malicious actor.\nConsent to application, Add service principal and Add OAuth2PermissionGrant should typically be rare events.\nThis may help detect the Oauth2 attack that can be initiated by this publicly available tool - https://github.com/fireeye/PwnAuth\nFor further information on AuditLogs please see https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities.'\n",
        "displayName": "Rare application consent",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "InitiatedBy",
                "identifier": "FullName"
              },
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "CloudApplication",
            "fieldMappings": [
              {
                "columnName": "TargetResourceName",
                "identifier": "Name"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/RareApplicationConsent.yaml",
        "query": "let current = 1d;\nlet auditLookback = 7d;\n// Setting threshold to 3 as a default, change as needed.\n// Any operation that has been initiated by a user or app more than 3 times in the past 7 days will be excluded\nlet threshold = 3;\n// Gather initial data from lookback period, excluding current, adjust current to more than a single day if no results\nlet AuditTrail = AuditLogs | where TimeGenerated >= ago(auditLookback) and TimeGenerated < ago(current)\n// 2 other operations that can be part of malicious activity in this situation are\n// \"Add OAuth2PermissionGrant\" and \"Add service principal\", extend the filter below to capture these too\n| where OperationName has \"Consent to application\"\n| extend InitiatedBy = iff(isnotempty(tostring(InitiatedBy.user.userPrincipalName)),\n          tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))\n| mv-apply TargetResource = TargetResources on \n  (\n      where TargetResource.type =~ \"ServicePrincipal\"\n      | extend TargetResourceName = tolower(tostring(TargetResource.displayName))\n  )\n| summarize max(TimeGenerated), OperationCount = count() by OperationName, InitiatedBy, TargetResourceName\n// only including operations initiated by a user or app that is above the threshold so we produce only rare and has not occurred in last 7 days\n| where OperationCount > threshold;\n// Gather current period of audit data\nlet RecentConsent = AuditLogs | where TimeGenerated >= ago(current)\n| where OperationName has \"Consent to application\"\n| extend IpAddress = case(\n              isnotempty(tostring(InitiatedBy.user.ipAddress)) and tostring(InitiatedBy.user.ipAddress) != 'null', tostring(InitiatedBy.user.ipAddress),\n              isnotempty(tostring(InitiatedBy.app.ipAddress)) and tostring(InitiatedBy.app.ipAddress) != 'null', tostring(InitiatedBy.app.ipAddress),\n              'Not Available')\n| extend InitiatedBy = iff(isnotempty(tostring(InitiatedBy.user.userPrincipalName)),\n                          tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))\n| mv-apply TargetResource = TargetResources on \n  (\n      where TargetResource.type =~ \"ServicePrincipal\"\n      | extend TargetResourceName = tolower(tostring(TargetResource.displayName)),\n               props = TargetResource.modifiedProperties\n  )\n| parse props with * \"ConsentType: \" ConsentType \"]\" *\n| mv-apply AdditionalDetail = AdditionalDetails on \n  (\n      where AdditionalDetail.key =~ \"User-Agent\"\n      | extend UserAgent = tostring(AdditionalDetail.value)\n  )\n| project TimeGenerated, InitiatedBy, IpAddress, TargetResourceName, Category, OperationName, ConsentType, UserAgent, CorrelationId, Type;\n// Exclude previously seen audit activity for \"Consent to application\" that was seen in the lookback period\n// First for rare InitiatedBy\nlet RareConsentBy = RecentConsent | join kind= leftanti AuditTrail on OperationName, InitiatedBy\n| extend Reason = \"Previously unseen user consenting\";\n// Second for rare TargetResourceName\nlet RareConsentApp = RecentConsent | join kind= leftanti AuditTrail on OperationName, TargetResourceName\n| extend Reason = \"Previously unseen app granted consent\";\nRareConsentBy | union RareConsentApp\n| summarize Reason = make_set(Reason,100) by TimeGenerated, InitiatedBy, IpAddress, TargetResourceName, Category, OperationName, ConsentType, UserAgent, CorrelationId, Type\n| extend timestamp = TimeGenerated, Name = tolower(tostring(split(InitiatedBy,'@',0)[0])), UPNSuffix = tolower(tostring(split(InitiatedBy,'@',1)[0]))\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P7D",
        "severity": "Medium",
        "status": "Available",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Persistence",
          "PrivilegeEscalation"
        ],
        "techniques": [
          "T1068",
          "T1136"
        ],
        "templateVersion": "1.1.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 3
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}