Solutions/Threat Intelligence (NEW)/Analytic Rules/FileHashEntity_DeviceFileEvents_Updated.yaml

id: d6f04915-4471-4cb3-b163-a8b72997cf72
name: TI map File Hash to DeviceFileEvents Event
description: |
  'Identifies a match in DeviceFileEvents Event data from any FileHash IOC from TI'
severity: Medium
requiredDataConnectors:
  - connectorId: MicrosoftThreatProtection
    dataTypes:
      - DeviceFileEvents
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let DeviceFileEvents_ = (union
  (DeviceFileEvents | where TimeGenerated > ago(dt_lookBack) | where isnotempty(SHA1) | extend FileHashValue = SHA1),
  (DeviceFileEvents | where TimeGenerated > ago(dt_lookBack) | where isnotempty(SHA256) | extend FileHashValue = SHA256));
  let Hashes = DeviceFileEvents_ | distinct FileHashValue;
  ThreatIntelIndicators
  //extract key part of kv pair
        | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
        | where isnotempty(IndicatorType) and IndicatorType == "file"
        | extend FileHashType = replace("'", "", substring(ObservableKey, indexof(ObservableKey, "hashes.") + 7, strlen(ObservableKey) - indexof(ObservableKey, "hashes.") - 7))
        | extend FileHashValue = toupper(ObservableValue)
        | extend IndicatorId = tostring(split(Id, "--")[2])
  | where isnotempty(FileHashValue)
  | where TimeGenerated > ago(ioc_lookBack)
  //  | where FileHashValue in (Hashes)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id
  | where IsActive == true and ValidUntil > now()
  | extend Description = tostring(parse_json(Data).description)
  | where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;"
    | project-reorder *, FileHashType, FileHashValue, Type
  | join kind=innerunique (DeviceFileEvents_) on $left.FileHashValue == $right.FileHashValue
  | where TimeGenerated < ValidUntil
  | summarize TimeGenerated = arg_max(TimeGenerated, *) by  IndicatorId, DeviceId
  | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
  | extend Description = tostring(parse_json(Data).description)
  | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
  | project TimeGenerated, TrafficLightProtocolLevel, Description, ActivityGroupNames, IndicatorId, FileHashValue, FileHashType, ValidUntil, Confidence, ActionType, DeviceId, DeviceName, FolderPath, RequestAccountDomain, RequestAccountName, RequestAccountSid, MachineGroup
  | extend timestamp = TimeGenerated
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: RequestAccountName
      - identifier: Sid
        columnName: RequestAccountSid
      - identifier: NTDomain
        columnName: RequestAccountDomain
  - entityType: FileHash
    fieldMappings:
      - identifier: Value
        columnName: FileHashValue
      - identifier: Algorithm
        columnName: FileHashType
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: DeviceName
version: 1.0.1
kind: Scheduled