Remote File Creation with PsExec

Status: available
Severity: high
Time window: 10m
Group by: DeviceId, DeviceName, InitiatingProcessFileName, TimeWindow
Source: github.com/Azure/Azure-Sentinel

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

MITRE ATT&CK coverage

Tactic	Techniques
Lateral Movement	`T1570` Lateral Tool Transfer

Event coverage

Provider	Event/ActionType	Title
Sysmon	Event ID 11	FileCreate
Security-Auditing	Event ID 4663	An attempt was made to access an object.
Defender-DeviceFileEvents	any	File activity (any)

Rule body kusto

id: 35ab0d58-baab-4154-87ed-fa2f69797e9e
name: 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
status: Available
requiredDataConnectors:
  - connectorId: MicrosoftThreatProtection
    dataTypes:
      - DeviceFileEvents
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - LateralMovement
relevantTechniques:
  - T1570
tags:
  - Ryuk
  - Ransomware
  - PsExec
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), "")
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: DeviceName
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain
version: 1.0.0
kind: Scheduled

Stages and Predicates

Stage 1: `source`

DeviceFileEvents

Stage 2: `where`

| where InitiatingProcessCommandLine has "accepteula"

Stage 3: `where`

| where FolderPath has "\\\\" and FileName endswith ".exe"

Stage 4: `extend`

| extend Exe = countof(InitiatingProcessCommandLine, ".exe")

Stage 5: `where`

| where InitiatingProcessCommandLine !has ".ps1" and Exe > 1 or
InitiatingProcessCommandLine has ".bat"

Stage 6: `where`

| where not(InitiatingProcessCommandLine has_any("batch", "auditpol",
"script", "scripts", "illusive", "rebootrequired"))

Stage 7: `summarize`

| 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

Threshold: gt 4

Stage 8: `where`

| where FileCount > 4

Stage 9: `extend`

| extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)

HostName =

ifDeviceName has "."substring(DeviceName, 0, indexof(DeviceName, '.'))

elseDeviceName

Stage 10: `extend`

| extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")

DnsDomain =

ifDeviceName has "."substring(DeviceName, (indexof(DeviceName, '.') + 1))

else""

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`InitiatingProcessCommandLine`	match	`batch`, `auditpol`, `script`, `scripts`, `illusive`, `rebootrequired`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`Exe`	gt	`1` transforms: `cased`
`FileCount`	gt	`4` transforms: `cased`
`FileName`	ends_with	`.exe` corpus 2 (kusto 2)
`FolderPath`	match	`\\\\` transforms: `term`
`InitiatingProcessCommandLine`	match	`.bat` transforms: `term` corpus 11 (sigma 9, elastic 1, kusto 1) `accepteula` transforms: `term` corpus 7 (sigma 3, kusto 3, splunk 1)

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`DeviceId`	`summarize`
`DeviceName`	`summarize`
`FileCount`	`summarize`
`InitiatingProcessFileName`	`summarize`
`TimeWindow`	`summarize`
`HostName`	`extend`
`DnsDomain`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Remote File Creation with PsExec

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `where`

Stage 6: `where`

Stage 7: `summarize`

Stage 8: `where`

Stage 9: `extend`

Stage 10: `extend`

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

Remote File Creation with PsExec

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend

Stage 5: where

Stage 6: where

Stage 7: summarize

Stage 8: where

Stage 9: extend

Stage 10: extend

Exclusions

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `where`

Stage 6: `where`

Stage 7: `summarize`

Stage 8: `where`

Stage 9: `extend`

Stage 10: `extend`