Detection rules › Kusto

CyberArkEPM - Unexpected executable location

Severity
medium
Time window
30m
Source
github.com/Azure/Azure-Sentinel

'Detects program run from unexpected location.'

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1204 User Execution
StealthT1036 Masquerading

Rule body kusto

id: c1fcbbd7-74f8-4f32-8116-0a533ebd3878
name: CyberArkEPM - Unexpected executable location
description: |
  'Detects program run from unexpected location.'
severity: Medium
requiredDataConnectors:
  - connectorId: CyberArkEPM
    dataTypes:
      - CyberArkEPM
queryFrequency: 30m
queryPeriod: 30m
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Execution
  - DefenseEvasion
relevantTechniques:
  - T1204
  - T1036
query: | 
  let susp_exe_folders = dynamic([@'\tmp\', @'\TEMP\', @'/tmp/', @'\Users\Public\', @'\$Recycle.bin', @'\Windows\Fonts\', @'$']);
  CyberArkEPM
  | where EventSubType != 'AttackAttempt'
  | where ActingProcessName has_any (susp_exe_folders)
  | project EventEndTime, EventMessage, ActorUsername, ActingProcessFileInternalName
  | extend AccountCustomEntity = ActorUsername
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountCustomEntity
version: 1.0.0
kind: Scheduled

Stages and Predicates

Parameters

let susp_exe_folders = dynamic([@'\tmp\', @'\TEMP\', @'/tmp/', @'\Users\Public\', @'\$Recycle.bin', @'\Windows\Fonts\', @'$']);

Stage 1: source

CyberArkEPM

Stage 2: where

| where EventSubType != 'AttackAttempt'

Stage 3: where

| where ActingProcessName has_any (susp_exe_folders)

Stage 4: project

| project EventEndTime, EventMessage, ActorUsername, ActingProcessFileInternalName

Stage 5: extend

| extend AccountCustomEntity = ActorUsername

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.

FieldKindValues
ActingProcessNamematch
  • $
  • /tmp/
  • \$Recycle.bin
  • \TEMP\
  • \Users\Public\
  • \Windows\Fonts\
  • \tmp\
EventSubTypene
  • AttackAttempt transforms: cased

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.

FieldSource
ActingProcessFileInternalNameproject
ActorUsernameproject
EventEndTimeproject
EventMessageproject
AccountCustomEntityextend