Privileged Accounts - Sign in Failure Spikes

id: 34c5aff9-a8c2-4601-9654-c7e46342d03b
name: Privileged Accounts - Sign in Failure Spikes
description: |
  ' Identifies spike in failed sign-ins from Privileged accounts. Privileged accounts list can be based on IdentityInfo UEBA table.
  Spike is determined based on Time series anomaly which will look at historical baseline values.
  Ref : https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-privileged-accounts#things-to-monitor'
severity: High
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - SigninLogs
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AADNonInteractiveUserSignInLogs
  - connectorId: BehaviorAnalytics
    dataTypes:
      - IdentityInfo
queryFrequency: 1d
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
status: Available
tactics:
  - InitialAccess
relevantTechniques:
  - T1078.004
tags:
  - AADSecOpsGuide
query: |
  let starttime = 14d;
  let timeframe = 1d;
  let scorethreshold = 3;
  let baselinethreshold = 5;
  let aadFunc = (tableName:string){
      IdentityInfo
      | where TimeGenerated > ago(starttime)
      | summarize arg_max(TimeGenerated, *) by AccountUPN
      | mv-expand AssignedRoles
      | where AssignedRoles contains 'Admin' or GroupMembership has "Admin"
      | summarize Roles = make_list(AssignedRoles) by AccountUPN = tolower(AccountUPN)
      | join kind=inner (
          table(tableName)
          | where TimeGenerated between (startofday(ago(starttime))..startofday(now()))
          | where ResultType != 0
          | extend UserPrincipalName = tolower(UserPrincipalName)
      ) on $left.AccountUPN == $right.UserPrincipalName
      | extend timestamp = TimeGenerated, AccountCustomEntity = UserPrincipalName, Roles = tostring(Roles)
  };
  let aadSignin = aadFunc("SigninLogs");
  let aadNonInt = aadFunc("AADNonInteractiveUserSignInLogs");
  let allSignins = union isfuzzy=true aadSignin, aadNonInt;
  let TimeSeriesAlerts = 
      allSignins
      | make-series HourlyCount=count() on TimeGenerated from startofday(ago(starttime)) to startofday(now()) step 1h by UserPrincipalName, Roles
      | extend (anomalies, score, baseline) = series_decompose_anomalies(HourlyCount, scorethreshold, -1, 'linefit')
      | mv-expand HourlyCount to typeof(double), TimeGenerated to typeof(datetime), anomalies to typeof(double), score to typeof(double), baseline to typeof(long)
      // Filtering low count events per baselinethreshold
      | where anomalies > 0 and baseline > baselinethreshold
      | extend AnomalyHour = TimeGenerated
      | project UserPrincipalName, Roles, AnomalyHour, TimeGenerated, HourlyCount, baseline, anomalies, score;
  // Filter the alerts for specified timeframe
  TimeSeriesAlerts
  | where TimeGenerated > startofday(ago(timeframe))
  | join kind=inner ( 
      allSignins
      | where TimeGenerated > startofday(ago(timeframe))
      // create a new column and round to hour
      | extend DateHour = bin(TimeGenerated, 1h)
      | summarize PartialFailedSignins = count(), LatestAnomalyTime = arg_max(TimeGenerated, *) by bin(TimeGenerated, 1h), OperationName, Category, ResultType, ResultDescription, UserPrincipalName, Roles, UserDisplayName, AppDisplayName, ClientAppUsed, IPAddress, ResourceDisplayName
  ) on UserPrincipalName, $left.AnomalyHour == $right.DateHour
  | project LatestAnomalyTime, OperationName, Category, UserPrincipalName, Roles = todynamic(Roles), UserDisplayName, ResultType, ResultDescription, AppDisplayName, ClientAppUsed, UserAgent, IPAddress, Location, AuthenticationRequirement, ConditionalAccessStatus, ResourceDisplayName, PartialFailedSignins, TotalFailedSignins = HourlyCount, baseline, anomalies, score
  | extend Name = tostring(split(UserPrincipalName,'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName,'@',1)[0])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserPrincipalName    
      - identifier: Name
        columnName: Name      
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPAddress
version: 1.1.1
kind: Scheduled