Windows.EventLogs.ExplicitLogon

This artifact enables querying for explicit logon events. i.e Event ID 4648: A logon was attempted using explicit credentials.

If logging is enabled, these events are generated on the source machine when an authentication attempt occurs under a different user context. Examples include a user authenticating to another machine using wmic or mapping a drive using different credentials, or using the RunAs option locally.

This artifact by default filters all events with localhost as the server and MACHINE$ as target user. A recommended hunt for lateral movement would be activity to other machines from commonly abused lolbins or explicit logon events from unusual processes.

name: Windows.EventLogs.ExplicitLogon
description: |
    This artifact enables querying for explicit logon events.  i.e Event ID 4648:
    A logon was attempted using explicit credentials.

    If logging is enabled, these events are generated on the source machine when
    an authentication attempt occurs under a different user context. Examples
    include a user authenticating to another machine using wmic or mapping a
    drive using different credentials, or using the RunAs option locally.

    This artifact by default filters all events with localhost as the server and
    MACHINE$ as target user. A recommended hunt for lateral movement would be
    activity to other machines from commonly abused lolbins or explicit logon
    events from unusual processes.


author: Matt Green - @mgreen27

precondition: SELECT OS From info() where OS = 'windows'

parameters:
  - name: EvtxGlob
    default: '%SystemRoot%\System32\Winevt\Logs\Security.evtx'
  - name: UsernameRegex
    description: "Target username Regex"
    default: .
    type: regex
  - name: UsernameWhitelist
    description: "Target username witelist Regex"
    default: '\\$$'
    type: regex
  - name: ServerRegex
    description: "Target server regex"
    default: .
    type: regex
  - name: ServerWhitelist
    description: "Target server whitelist regex"
    default: 'localhost'
    type: regex
  - name: ProcessNameRegex
    description: "Target process Regex"
    default: .
  - name: ProcessNameWhitelist
    description: "Target process whitelist Regex"
    type: regex

  - name: VSSAnalysisAge
    type: int
    default: 0
    description: |
      If larger than zero we analyze VSS within this many days
      ago. (e.g 7 will analyze all VSS within the last week).  Note
      that when using VSS analysis we have to use the ntfs accessor
      for everything which will be much slower.

  - name: DateAfter
    type: timestamp
    description: "search for events after this date. YYYY-MM-DDTmm:hh:ssZ"
  - name: DateBefore
    type: timestamp
    description: "search for events before this date. YYYY-MM-DDTmm:hh:ssZ"


sources:
  - query: |
      LET VSS_MAX_AGE_DAYS <= VSSAnalysisAge
      LET Accessor = if(condition=VSSAnalysisAge > 0, then="ntfs_vss", else="auto")

      -- firstly set timebounds for performance
      LET DateAfterTime <= if(condition=DateAfter,
        then=timestamp(epoch=DateAfter), else=timestamp(epoch="1600-01-01"))
      LET DateBeforeTime <= if(condition=DateBefore,
        then=timestamp(epoch=DateBefore), else=timestamp(epoch="2200-01-01"))

      -- expand provided glob into a list of paths on the file system (fs)
      LET fspaths = SELECT OSPath
        FROM glob(globs=expand(path=EvtxGlob), accessor=Accessor)

      -- function returning IOC hits
      LET evtxsearch(PathList) = SELECT * FROM foreach(
            row=PathList,
            query={
                SELECT
                    timestamp(epoch=int(int=System.TimeCreated.SystemTime)) AS EventTime,
                    System.Computer as Computer,
                    System.EventID.Value as EventID,
                    System.EventRecordID as EventRecordID,
                    EventData.SubjectUserName as SubjectUserName,
                    EventData.SubjectDomainName as SubjectDomainName,
                    EventData.TargetUserName as TargetUserName,
                    EventData.TargetDomainName as TargetDomainName,
                    EventData.TargetServerName as TargetServerName,
                    EventData.ProcessName as ProcessName,
                    EventData,
                    Message,
                    OSPath
                FROM parse_evtx(filename=OSPath, accessor=Accessor)
                WHERE
                    EventID = 4648
                    AND EventTime < DateBeforeTime
                    AND EventTime > DateAfterTime
                    AND TargetUserName =~ UsernameRegex
                    AND NOT if(condition=UsernameWhitelist,
                        then= TargetUserName =~ UsernameWhitelist,
                        else= FALSE)
                    AND TargetServerName =~ ServerRegex
                    AND NOT if(condition=ServerWhitelist,
                        then= TargetServerName =~ ServerWhitelist,
                        else= FALSE)
                    AND ProcessName =~ ProcessNameRegex
                    AND NOT if(condition=ProcessNameWhitelist,
                        then= ProcessName =~ ProcessNameWhitelist,
                        else= FALSE)
            }
          )

        SELECT * FROM evtxsearch(PathList=fspaths)