AD FS Remote Auth Sync Connection

id: 2f4165a6-c4fb-4e94-861e-37f1b4d6c0e6
name: AD FS Remote Auth Sync Connection
description: |
  'This detection uses Security events from the "AD FS Auditing" provider to detect suspicious authentication events on an AD FS server. The results then get correlated with events from the Windows Filtering Platform (WFP) to detect suspicious incoming network traffic on port 80 on the AD FS server.
  This could be a sign of a threat actor trying to use replication services on the AD FS server to get its configuration settings and extract sensitive information such as AD FS certificates. In order to use this query you need to enable AD FS auditing on the AD FS Server.
  References:
  https://docs.microsoft.com/windows-server/identity/ad-fs/troubleshooting/ad-fs-tshoot-logging
  https://twitter.com/OTR_Community/status/1387038995016732672'
severity: Medium
requiredDataConnectors:
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsSecurityEvents
    dataTypes:
      - SecurityEvent
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
status: Available
tactics:
  - Collection
relevantTechniques:
  - T1005
tags:
  - SimuLand
query: |
  // Adjust this to use a longer timeframe to identify ADFS servers
  //let lookback = 0d;
  // Adjust this to adjust detection timeframe
  //let timeframe = 1d;
  // SamAccountName of AD FS Service Account. Filter on the use of a specific AD FS user account
  //let adfsuser = 'adfsadmin';
  // Identify ADFS Servers
  let ADFS_Servers = (
      SecurityEvent
      //| where TimeGenerated > ago(timeframe+lookback)
      | where EventSourceName == 'AD FS Auditing'
      | distinct Computer
  );
  SecurityEvent
      //| where TimeGenerated > ago(timeframe)
      | where Computer in~ (ADFS_Servers)
      // A token of type 'http://schemas.microsoft.com/ws/2006/05/servicemodel/tokens/SecureConversation'
      // for relying party '-' was successfully authenticated.
      | where EventID == 412
      | extend EventData = parse_xml(EventData).EventData.Data
      | extend InstanceId = tostring(EventData[0])
  | join kind=inner
  (
      SecurityEvent
      //| where TimeGenerated > ago(timeframe)
      | where Computer in~ (ADFS_Servers)
      // Events to identify caller identity from event 412
      | where EventID == 501
      | extend EventData = parse_xml(EventData).EventData.Data
      | where tostring(EventData[1]) contains 'identity/claims/name'
      | extend InstanceId = tostring(EventData[0])
      | extend ClaimsName = tostring(EventData[2])
      // Filter on the use of a specific AD FS user account
      //| where ClaimsName contains adfsuser
  )
  on $left.InstanceId == $right.InstanceId
  | join kind=inner
  (
      SecurityEvent
      | where EventID == 5156
      | where Computer in~ (ADFS_Servers)
      | extend EventData = parse_xml(EventData).EventData.Data
      | mv-expand bagexpansion=array EventData
      | evaluate bag_unpack(EventData)
      | extend Key = tostring(column_ifexists('@Name', "")), Value = column_ifexists('#text', "")
      | evaluate pivot(Key, any(Value), TimeGenerated, Computer, EventID)
      | extend DestPort = column_ifexists("DestPort", ""),
            Direction = column_ifexists("Direction", ""),
            Application = column_ifexists("Application", ""),
            DestAddress = column_ifexists("DestAddress", ""),
            SourceAddress = column_ifexists("SourceAddress", ""),
            SourcePort = column_ifexists("SourcePort", "")
      // Look for inbound connections from endpoints on port 80
      | where DestPort == 80 and Direction == '%%14592' and Application == 'System'
      | where DestAddress !in ('::1','0:0:0:0:0:0:0:1')
  )
  on $left.Computer == $right.Computer
  | project TimeGenerated, Computer, ClaimsName, SourceAddress, SourcePort
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | extend AccountName = tostring(split(ClaimsName, @'\')[1]), AccountNTDomain = tostring(split(ClaimsName, @'\')[0])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: ClaimsName
      - identifier: Name
        columnName: AccountName
      - identifier: NTDomain
        columnName: AccountNTDomain
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: HostNameDomain
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceAddress
version: 1.0.4
kind: Scheduled