Dev-0530 File Extension Rename

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Id	d82eb796-d1eb-43c8-a813-325ce3417cef
Rulename	Dev-0530 File Extension Rename
Description	Dev-0530 actors are known to encrypt the contents of the victims device as well as renaming the file extensions. This query looks for the creation of files with .h0lyenc extension or presence of ransom note.
Severity	High
Tactics	Impact
Techniques	T1486
Required data connectors	MicrosoftThreatProtection
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/MultipleDataSources/Dev-0530_FileExtRename.yaml
Version	1.1.1
Arm template	d82eb796-d1eb-43c8-a813-325ce3417cef.json

KQL

union isfuzzy=true
    (DeviceFileEvents
    | where ActionType == "FileCreated"
    | where FileName endswith ".h0lyenc" or FolderPath == "C:\\FOR_DECRYPT.html"
    | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated)
        by
        AccountName = InitiatingProcessAccountName, AccountDomain = InitiatingProcessAccountDomain,
        DeviceName,
        Type,
        InitiatingProcessId,
        FileName,
        FolderPath,
        EventType = ActionType,
        Commandline = InitiatingProcessCommandLine,
        InitiatingProcessFileName,
        InitiatingProcessSHA256,
        FileHashCustomEntity = SHA256,
        AlgorithmCustomEntity = "SHA256"
    | extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
    | extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)
    ),
    (imFileEvent
    | where EventType == "FileCreated"
    | where TargetFilePath endswith ".h0lyenc" or TargetFilePath == "C:\\FOR_DECRYPT.html"
    | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated)
        by
        ActorUsername,
        DvcHostname,
        DvcDomain,
        DvcId,
        Type,
        EventType,
        FileHashCustomEntity = TargetFileSHA256,
        Hash,
        TargetFilePath,
        Commandline = ActingProcessCommandLine,
        AlgorithmCustomEntity = "SHA256"
    | extend AccountName = tostring(split(ActorUsername, @'\')[1]), AccountDomain = tostring(split(ActorUsername, @'\')[0])
    | extend HostName = DvcHostname, HostNameDomain = DvcDomain
    | extend DeviceName = strcat(DvcHostname, ".", DvcDomain )
    )

YAML

tags:
- Dev-0530
- Schema: ASIMFileEvent
  SchemaVersion: 0.1.0
id: d82eb796-d1eb-43c8-a813-325ce3417cef
description: |
    'Dev-0530 actors are known to encrypt the contents of the victims device as well as renaming the file extensions. This query looks for the creation of files with .h0lyenc extension or presence of ransom note.'
triggerThreshold: 0
entityMappings:
- fieldMappings:
  - columnName: ActorUserName
    identifier: FullName
  - columnName: AccountName
    identifier: Name
  - columnName: AccountDomain
    identifier: NTDomain
  entityType: Account
- fieldMappings:
  - columnName: DeviceName
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: HostNameDomain
    identifier: DnsDomain
  entityType: Host
- fieldMappings:
  - columnName: AlgorithmCustomEntity
    identifier: Algorithm
  - columnName: FileHashCustomEntity
    identifier: Value
  entityType: FileHash
version: 1.1.1
triggerOperator: gt
query: |
  union isfuzzy=true
      (DeviceFileEvents
      | where ActionType == "FileCreated"
      | where FileName endswith ".h0lyenc" or FolderPath == "C:\\FOR_DECRYPT.html"
      | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated)
          by
          AccountName = InitiatingProcessAccountName, AccountDomain = InitiatingProcessAccountDomain,
          DeviceName,
          Type,
          InitiatingProcessId,
          FileName,
          FolderPath,
          EventType = ActionType,
          Commandline = InitiatingProcessCommandLine,
          InitiatingProcessFileName,
          InitiatingProcessSHA256,
          FileHashCustomEntity = SHA256,
          AlgorithmCustomEntity = "SHA256"
      | extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
      | extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)
      ),
      (imFileEvent
      | where EventType == "FileCreated"
      | where TargetFilePath endswith ".h0lyenc" or TargetFilePath == "C:\\FOR_DECRYPT.html"
      | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated)
          by
          ActorUsername,
          DvcHostname,
          DvcDomain,
          DvcId,
          Type,
          EventType,
          FileHashCustomEntity = TargetFileSHA256,
          Hash,
          TargetFilePath,
          Commandline = ActingProcessCommandLine,
          AlgorithmCustomEntity = "SHA256"
      | extend AccountName = tostring(split(ActorUsername, @'\')[1]), AccountDomain = tostring(split(ActorUsername, @'\')[0])
      | extend HostName = DvcHostname, HostNameDomain = DvcDomain
      | extend DeviceName = strcat(DvcHostname, ".", DvcDomain )
      )  
tactics:
- Impact
kind: Scheduled
queryFrequency: 1d
name: Dev-0530 File Extension Rename
severity: High
metadata:
  author:
    name: Microsoft Security Research
  source:
    kind: Community
  categories:
    domains:
    - Security - Others
  support:
    tier: Community
queryPeriod: 1d
requiredDataConnectors:
- dataTypes:
  - DeviceFileEvents
  connectorId: MicrosoftThreatProtection
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/MultipleDataSources/Dev-0530_FileExtRename.yaml
relevantTechniques:
- T1486

ARM