Detecting Impossible travel with mailbox permission tampering & Privilege Escalation attempt

id: 1399664f-9434-497c-9cde-42e4d74ae20e
name: Detecting Impossible travel with mailbox permission tampering & Privilege Escalation attempt
description: |
  'This hunting query will alert on any Impossible travel activity in correlation with mailbox permission tampering followed by account being added to a PIM managed privileged group.
  Ensure this impossible travel incident with increase of privileges is legitimate in your environment.'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureSecurityCenter
    dataTypes:
      - SecurityAlert (ASC)
  - connectorId: Office365
    dataTypes:
      - OfficeActivity
  - connectorId: AzureActivity
    dataTypes:
      - AzureActivity
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AuditLogs
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - PrivilegeEscalation
relevantTechniques:
  - T1078
  - T1548
query: |
  SecurityAlert 
  | where AlertName == "Impossible travel activity"
  | extend Extprop = parsejson(Entities)
  | mv-expand Extprop
  | extend Extprop = parsejson(Extprop)
  | extend CmdLine = iff(Extprop['Type']=="process", Extprop['CommandLine'], '')
  | extend File = iff(Extprop['Type']=="file", Extprop['Name'], '')
  | extend Account = Extprop['Name']
  | extend Domain = Extprop['UPNSuffix']
  | extend Account = iif(isnotempty(Domain) and Extprop['Type']=="account", tolower(strcat(Account, "@", Domain)), iif(Extprop['Type']=="account", tolower(Account), ""))
  | extend IpAddress = iff(Extprop["Type"] == "ip",Extprop['Address'], '')
  | extend Process = iff(isnotempty(CmdLine), CmdLine, File)
  | project TimeGenerated,Account,IpAddress,CompromisedEntity,Description,ProviderName,ResourceId
  | join kind=inner
  (
  OfficeActivity
  | where Operation =~ "Add-MailboxPermission"
  | extend value = tostring(parse_json(Parameters)[3].Value)
  | where value contains "FullAccess"
  | where ResultStatus == "True"
  | project Parameters,TimeGenerated,value,RecordType,Operation,OrganizationId,UserType,UserKey,OfficeWorkload,ResultStatus,OfficeObjectId,UserId,ClientIP,ExternalAccess,OriginatingServer,OrganizationName,TenantId,ElevationTime,SourceSystem,OfficeId,OfficeTenantId,Type,SourceRecordId
  ) on $left.Account == $right.UserId
  | join kind=inner
  (
  AuditLogs
  | where ActivityDisplayName =~ "Add eligible member to role in PIM requested (timebound)"
  | where AADOperationType =~ "CreateRequestEligibleRole"
  | where TargetResources has_any ("-PRIV", "Administrator", "Security")
  | extend BuiltinRole = tostring(parse_json(TargetResources[0].displayName))
  | extend CustomGroup = tostring(parse_json(TargetResources[3].displayName))
  | extend TargetAccount = tostring(parse_json(TargetResources[2].displayName))
  | extend Initiatedby = Identity
  | project TimeGenerated, ActivityDisplayName, AADOperationType, Initiatedby, TargetAccount, BuiltinRole, CustomGroup, LoggedByService, Result, ResourceId, Id
  | sort by TimeGenerated desc
  ) on $left.UserId == $right.Initiatedby
  | extend AccountName = tostring(split(Initiatedby, "@")[0]), AccountUPNSuffix = tostring(split(Initiatedby, "@")[1])
  | project AADOperationType, ActivityDisplayName,AccountName, AccountUPNSuffix, Id,ResourceId,IpAddress
  
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IpAddress
version: 1.0.3
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]