MFA Rejected by User

let riskScoreCutoff = 3; //Adjust this score threshold based on volume of results. Activities identified as the most abnormal receive the highest scores (on a scale of 0-10)
SigninLogs
| where ResultType == 500121
| extend additionalDetails_ = tostring(Status.additionalDetails)
| extend UserPrincipalName = tolower(UserPrincipalName)
| where additionalDetails_ =~ "MFA denied; user declined the authentication" or additionalDetails_ has "fraud"
| summarize StartTime = min(TimeGenerated), EndTIme = max(TimeGenerated) by UserPrincipalName, UserId, AADTenantId, FailedIPAddress = IPAddress
| extend Name = tostring(split(UserPrincipalName,'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName,'@',1)[0])
| join kind=leftouter (
    IdentityInfo
    | summarize LatestReportTime = arg_max(TimeGenerated, *) by AccountUPN
    | project AccountUPN, Tags, JobTitle, GroupMembership, AssignedRoles, UserType, IsAccountEnabled
    | summarize
        Tags = make_set(Tags, 1000),
        GroupMembership = make_set(GroupMembership, 1000),
        AssignedRoles = make_set(AssignedRoles, 1000),
        UserType = make_set(UserType, 1000),
        UserAccountControl = make_set(UserType, 1000)
    by AccountUPN
    | extend UserPrincipalName=tolower(AccountUPN)
) on UserPrincipalName
//Below it will be joined with BehaviorAnalytics table to the Failed IP Addresses
| join kind=leftouter (
    BehaviorAnalytics
    | where ActivityType in ("FailedLogOn", "LogOn")
    | where isnotempty(SourceIPAddress)
    | project UsersInsights, DevicesInsights, ActivityInsights, InvestigationPriority, SourceIPAddress, UserName
    | project-rename FailedIPAddress = SourceIPAddress, Name = UserName
    | summarize
      MaxInvestigationScore = max(InvestigationPriority)  // Only retrieve maximum Investigation Property score for both FailedIP and User
    by FailedIPAddress, Name)
on FailedIPAddress, Name  // Joining on both IP and User so as to only return context associated with same user
| extend UEBARiskScore = MaxInvestigationScore
| project-away *1 // removing duplicate columns post outer join from output
| where  UEBARiskScore > riskScoreCutoff
| sort by UEBARiskScore desc 

kind: Scheduled
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: UserPrincipalName
    identifier: FullName
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
- entityType: Account
  fieldMappings:
  - columnName: UserId
    identifier: AadUserId
- entityType: IP
  fieldMappings:
  - columnName: FailedIPAddress
    identifier: Address
description: |
  'Identifies occurances where a user has rejected an MFA prompt. This could be an indicator that a threat actor has compromised the username and password of this user account and is using it to try and log into the account.
  Ref : https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#monitoring-for-failed-unusual-sign-ins
  This query has also been updated to include UEBA logs IdentityInfo and BehaviorAnalytics for contextual information around the results. 
  Please note, MFA Failed logons from known IP ranges can be benign depending on the conditional access policies. In case of noisy behavior, consider tuning the source IP ranges or location filter after careful consideration'  
severity: Medium
queryFrequency: 1h
triggerThreshold: 0
relevantTechniques:
- T1078.004
tags:
- AADSecOpsGuide
status: Available
tactics:
- InitialAccess
name: MFA Rejected by User
id: d99cf5c3-d660-436c-895b-8a8f8448da23
query: |
  let riskScoreCutoff = 3; //Adjust this score threshold based on volume of results. Activities identified as the most abnormal receive the highest scores (on a scale of 0-10)
  SigninLogs
  | where ResultType == 500121
  | extend additionalDetails_ = tostring(Status.additionalDetails)
  | extend UserPrincipalName = tolower(UserPrincipalName)
  | where additionalDetails_ =~ "MFA denied; user declined the authentication" or additionalDetails_ has "fraud"
  | summarize StartTime = min(TimeGenerated), EndTIme = max(TimeGenerated) by UserPrincipalName, UserId, AADTenantId, FailedIPAddress = IPAddress
  | extend Name = tostring(split(UserPrincipalName,'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName,'@',1)[0])
  | join kind=leftouter (
      IdentityInfo
      | summarize LatestReportTime = arg_max(TimeGenerated, *) by AccountUPN
      | project AccountUPN, Tags, JobTitle, GroupMembership, AssignedRoles, UserType, IsAccountEnabled
      | summarize
          Tags = make_set(Tags, 1000),
          GroupMembership = make_set(GroupMembership, 1000),
          AssignedRoles = make_set(AssignedRoles, 1000),
          UserType = make_set(UserType, 1000),
          UserAccountControl = make_set(UserType, 1000)
      by AccountUPN
      | extend UserPrincipalName=tolower(AccountUPN)
  ) on UserPrincipalName
  //Below it will be joined with BehaviorAnalytics table to the Failed IP Addresses
  | join kind=leftouter (
      BehaviorAnalytics
      | where ActivityType in ("FailedLogOn", "LogOn")
      | where isnotempty(SourceIPAddress)
      | project UsersInsights, DevicesInsights, ActivityInsights, InvestigationPriority, SourceIPAddress, UserName
      | project-rename FailedIPAddress = SourceIPAddress, Name = UserName
      | summarize
        MaxInvestigationScore = max(InvestigationPriority)  // Only retrieve maximum Investigation Property score for both FailedIP and User
      by FailedIPAddress, Name)
  on FailedIPAddress, Name  // Joining on both IP and User so as to only return context associated with same user
  | extend UEBARiskScore = MaxInvestigationScore
  | project-away *1 // removing duplicate columns post outer join from output
  | where  UEBARiskScore > riskScoreCutoff
  | sort by UEBARiskScore desc   
requiredDataConnectors:
- dataTypes:
  - SigninLogs
  connectorId: AzureActiveDirectory
- dataTypes:
  - BehaviorAnalytics
  connectorId: BehaviorAnalytics
- dataTypes:
  - IdentityInfo
  connectorId: BehaviorAnalytics
version: 2.0.4
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/MFARejectedbyUser.yaml
queryPeriod: 1h

{
  "$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/d99cf5c3-d660-436c-895b-8a8f8448da23')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/d99cf5c3-d660-436c-895b-8a8f8448da23')]",
      "properties": {
        "alertRuleTemplateName": "d99cf5c3-d660-436c-895b-8a8f8448da23",
        "customDetails": null,
        "description": "'Identifies occurances where a user has rejected an MFA prompt. This could be an indicator that a threat actor has compromised the username and password of this user account and is using it to try and log into the account.\nRef : https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#monitoring-for-failed-unusual-sign-ins\nThis query has also been updated to include UEBA logs IdentityInfo and BehaviorAnalytics for contextual information around the results. \nPlease note, MFA Failed logons from known IP ranges can be benign depending on the conditional access policies. In case of noisy behavior, consider tuning the source IP ranges or location filter after careful consideration'\n",
        "displayName": "MFA Rejected by User",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "UserPrincipalName",
                "identifier": "FullName"
              },
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "UserId",
                "identifier": "AadUserId"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "FailedIPAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/MFARejectedbyUser.yaml",
        "query": "let riskScoreCutoff = 3; //Adjust this score threshold based on volume of results. Activities identified as the most abnormal receive the highest scores (on a scale of 0-10)\nSigninLogs\n| where ResultType == 500121\n| extend additionalDetails_ = tostring(Status.additionalDetails)\n| extend UserPrincipalName = tolower(UserPrincipalName)\n| where additionalDetails_ =~ \"MFA denied; user declined the authentication\" or additionalDetails_ has \"fraud\"\n| summarize StartTime = min(TimeGenerated), EndTIme = max(TimeGenerated) by UserPrincipalName, UserId, AADTenantId, FailedIPAddress = IPAddress\n| extend Name = tostring(split(UserPrincipalName,'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName,'@',1)[0])\n| join kind=leftouter (\n    IdentityInfo\n    | summarize LatestReportTime = arg_max(TimeGenerated, *) by AccountUPN\n    | project AccountUPN, Tags, JobTitle, GroupMembership, AssignedRoles, UserType, IsAccountEnabled\n    | summarize\n        Tags = make_set(Tags, 1000),\n        GroupMembership = make_set(GroupMembership, 1000),\n        AssignedRoles = make_set(AssignedRoles, 1000),\n        UserType = make_set(UserType, 1000),\n        UserAccountControl = make_set(UserType, 1000)\n    by AccountUPN\n    | extend UserPrincipalName=tolower(AccountUPN)\n) on UserPrincipalName\n//Below it will be joined with BehaviorAnalytics table to the Failed IP Addresses\n| join kind=leftouter (\n    BehaviorAnalytics\n    | where ActivityType in (\"FailedLogOn\", \"LogOn\")\n    | where isnotempty(SourceIPAddress)\n    | project UsersInsights, DevicesInsights, ActivityInsights, InvestigationPriority, SourceIPAddress, UserName\n    | project-rename FailedIPAddress = SourceIPAddress, Name = UserName\n    | summarize\n      MaxInvestigationScore = max(InvestigationPriority)  // Only retrieve maximum Investigation Property score for both FailedIP and User\n    by FailedIPAddress, Name)\non FailedIPAddress, Name  // Joining on both IP and User so as to only return context associated with same user\n| extend UEBARiskScore = MaxInvestigationScore\n| project-away *1 // removing duplicate columns post outer join from output\n| where  UEBARiskScore > riskScoreCutoff\n| sort by UEBARiskScore desc \n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [
          "T1078.004"
        ],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "tags": [
          "AADSecOpsGuide"
        ],
        "techniques": [
          "T1078"
        ],
        "templateVersion": "2.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}