Remote File Creation with PsExec

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Id	35ab0d58-baab-4154-87ed-fa2f69797e9e
Rulename	Remote File Creation with PsExec
Description	This query was originally published in the threat analytics report, Ryuk ransomware. There is also a related blog. Ryuk is human-operated ransomware. Much like DoppelPaymer ransomware, Ryuk is spread manually, often on networks that are already infected with Trickbot. Ryuk operators use PsExec to manually spread the ransomware to other devices. The following query detects remote file creation events that might indicate an active attack. The See also section below lists links to other queries associated with Ryuk ransomware. References: https://www.microsoft.com/security/blog/2020/03/05/human-operated-ransomware-attacks-a-preventable-disaster/ https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Ransom:Win32/Ryuk.AA https://www.microsoft.com/security/blog/2020/03/05/human-operated-ransomware-attacks-a-preventable-disaster/ https://docs.microsoft.com/sysinternals/downloads/psexec
Severity	High
Tactics	LateralMovement
Techniques	T1570
Required data connectors	MicrosoftThreatProtection
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Lateral Movement/RemoteFileCreationWithPsExec.yaml
Version	1.0.0
Arm template	35ab0d58-baab-4154-87ed-fa2f69797e9e.json

KQL

// Find PsExec creating multiple files on remote machines in a 10-minute window
DeviceFileEvents
// Looking for PsExec by accepteula command flag
| where InitiatingProcessCommandLine has "accepteula"
// Remote machines and file is exe
| where FolderPath has "\\\\" and FileName endswith ".exe"
| extend Exe = countof(InitiatingProcessCommandLine, ".exe")
// Checking to see if command line has 2 .exe or .bat
| where InitiatingProcessCommandLine !has ".ps1" and Exe > 1 or
InitiatingProcessCommandLine has ".bat"
// Exclusions: Remove the following line to widen scope of AHQ
| where not(InitiatingProcessCommandLine has_any("batch", "auditpol",
"script", "scripts", "illusive", "rebootrequired"))
| summarize FileCount = dcount(FolderPath), make_set(SHA1, 100000), make_set(FolderPath, 100000),
make_set(FileName, 100000), make_set(InitiatingProcessCommandLine, 100000) by DeviceId, DeviceName,
TimeWindow=bin(TimeGenerated, 10m), InitiatingProcessFileName
| where FileCount > 4
| extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
| extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")

YAML

name: Remote File Creation with PsExec
relevantTechniques:
- T1570
id: 35ab0d58-baab-4154-87ed-fa2f69797e9e
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Lateral Movement/RemoteFileCreationWithPsExec.yaml
requiredDataConnectors:
- dataTypes:
  - DeviceFileEvents
  connectorId: MicrosoftThreatProtection
version: 1.0.0
severity: High
triggerThreshold: 0
tags:
- Ryuk
- Ransomware
- PsExec
queryPeriod: 1h
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: DeviceName
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: DnsDomain
  entityType: Host
queryFrequency: 1h
status: Available
query: |
  // Find PsExec creating multiple files on remote machines in a 10-minute window
  DeviceFileEvents
  // Looking for PsExec by accepteula command flag
  | where InitiatingProcessCommandLine has "accepteula"
  // Remote machines and file is exe
  | where FolderPath has "\\\\" and FileName endswith ".exe"
  | extend Exe = countof(InitiatingProcessCommandLine, ".exe")
  // Checking to see if command line has 2 .exe or .bat
  | where InitiatingProcessCommandLine !has ".ps1" and Exe > 1 or
  InitiatingProcessCommandLine has ".bat"
  // Exclusions: Remove the following line to widen scope of AHQ
  | where not(InitiatingProcessCommandLine has_any("batch", "auditpol",
  "script", "scripts", "illusive", "rebootrequired"))
  | summarize FileCount = dcount(FolderPath), make_set(SHA1, 100000), make_set(FolderPath, 100000),
  make_set(FileName, 100000), make_set(InitiatingProcessCommandLine, 100000) by DeviceId, DeviceName,
  TimeWindow=bin(TimeGenerated, 10m), InitiatingProcessFileName
  | where FileCount > 4
  | extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
  | extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")  
tactics:
- LateralMovement
kind: Scheduled
description: |
  This query was originally published in the threat analytics report, Ryuk ransomware. There is also a related blog.
  Ryuk is human-operated ransomware. Much like DoppelPaymer ransomware, Ryuk is spread manually, often on networks that are already infected with Trickbot.
  Ryuk operators use PsExec to manually spread the ransomware to other devices.
  The following query detects remote file creation events that might indicate an active attack.
  The See also section below lists links to other queries associated with Ryuk ransomware.
  References:
  https://www.microsoft.com/security/blog/2020/03/05/human-operated-ransomware-attacks-a-preventable-disaster/
  https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Ransom:Win32/Ryuk.AA
  https://www.microsoft.com/security/blog/2020/03/05/human-operated-ransomware-attacks-a-preventable-disaster/
  https://docs.microsoft.com/sysinternals/downloads/psexec  
triggerOperator: gt

ARM