Execution from Unusual Directory - Command Line

Identifies process execution from suspicious default Windows directories. This may be abused by adversaries to hide malware in trusted paths.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.*
logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

Elastic
Host
Windows
Threat Detection
Execution
Defense Evasion

Version: 8

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

edit

## Triage and analysis

This is related to the `Process Execution from an Unusual Directory rule`.

## Setup

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule query

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process where event.type in ("start", "process_started", "info") and
  process.name : ("wscript.exe",
                  "cscript.exe",
                  "rundll32.exe",
                  "regsvr32.exe",
                  "cmstp.exe",
                  "RegAsm.exe",
                  "installutil.exe",
                  "mshta.exe",
                  "RegSvcs.exe",
                  "powershell.exe",
                  "pwsh.exe",
                  "cmd.exe") and

  /* add suspicious execution paths here */
  process.args : ("C:\\PerfLogs\\*",
                  "C:\\Users\\Public\\*",
                  "C:\\Windows\\Tasks\\*",
                  "C:\\Intel\\*",
                  "C:\\AMD\\Temp\\*",
                  "C:\\Windows\\AppReadiness\\*",
                  "C:\\Windows\\ServiceState\\*",
                  "C:\\Windows\\security\\*",
                  "C:\\Windows\\IdentityCRL\\*",
                  "C:\\Windows\\Branding\\*",
                  "C:\\Windows\\csc\\*",
                  "C:\\Windows\\DigitalLocker\\*",
                  "C:\\Windows\\en-US\\*",
                  "C:\\Windows\\wlansvc\\*",
                  "C:\\Windows\\Prefetch\\*",
                  "C:\\Windows\\Fonts\\*",
                  "C:\\Windows\\diagnostics\\*",
                  "C:\\Windows\\TAPI\\*",
                  "C:\\Windows\\INF\\*",
                  "C:\\Windows\\System32\\Speech\\*",
                  "C:\\windows\\tracing\\*",
                  "c:\\windows\\IME\\*",
                  "c:\\Windows\\Performance\\*",
                  "c:\\windows\\intel\\*",
                  "c:\\windows\\ms\\*",
                  "C:\\Windows\\dot3svc\\*",
                  "C:\\Windows\\panther\\*",
                  "C:\\Windows\\RemotePackages\\*",
                  "C:\\Windows\\OCR\\*",
                  "C:\\Windows\\appcompat\\*",
                  "C:\\Windows\\apppatch\\*",
                  "C:\\Windows\\addins\\*",
                  "C:\\Windows\\Setup\\*",
                  "C:\\Windows\\Help\\*",
                  "C:\\Windows\\SKB\\*",
                  "C:\\Windows\\Vss\\*",
                  "C:\\Windows\\servicing\\*",
                  "C:\\Windows\\CbsTemp\\*",
                  "C:\\Windows\\Logs\\*",
                  "C:\\Windows\\WaaS\\*",
                  "C:\\Windows\\twain_32\\*",
                  "C:\\Windows\\ShellExperiences\\*",
                  "C:\\Windows\\ShellComponents\\*",
                  "C:\\Windows\\PLA\\*",
                  "C:\\Windows\\Migration\\*",
                  "C:\\Windows\\debug\\*",
                  "C:\\Windows\\Cursors\\*",
                  "C:\\Windows\\Containers\\*",
                  "C:\\Windows\\Boot\\*",
                  "C:\\Windows\\bcastdvr\\*",
                  "C:\\Windows\\TextInput\\*",
                  "C:\\Windows\\security\\*",
                  "C:\\Windows\\schemas\\*",
                  "C:\\Windows\\SchCache\\*",
                  "C:\\Windows\\Resources\\*",
                  "C:\\Windows\\rescache\\*",
                  "C:\\Windows\\Provisioning\\*",
                  "C:\\Windows\\PrintDialog\\*",
                  "C:\\Windows\\PolicyDefinitions\\*",
                  "C:\\Windows\\media\\*",
                  "C:\\Windows\\Globalization\\*",
                  "C:\\Windows\\L2Schemas\\*",
                  "C:\\Windows\\LiveKernelReports\\*",
                  "C:\\Windows\\ModemLogs\\*",
                  "C:\\Windows\\ImmersiveControlPanel\\*",
                  "C:\\$Recycle.Bin\\*") and

  /* noisy FP patterns */

  not process.parent.executable : ("C:\\WINDOWS\\System32\\DriverStore\\FileRepository\\*\\igfxCUIService*.exe",
                                   "C:\\Windows\\System32\\spacedeskService.exe",
                                   "C:\\Program Files\\Dell\\SupportAssistAgent\\SRE\\SRE.exe") and
  not (process.name : "rundll32.exe" and
       process.args : ("uxtheme.dll,#64",
                       "PRINTUI.DLL,PrintUIEntry",
                       "?:\\Windows\\System32\\FirewallControlPanel.dll,ShowNotificationDialog",
                       "?:\\WINDOWS\\system32\\Speech\\SpeechUX\\sapi.cpl",
                       "?:\\Windows\\system32\\shell32.dll,OpenAs_RunDLL")) and

  not (process.name : "cscript.exe" and process.args : "?:\\WINDOWS\\system32\\calluxxprovider.vbs") and

  not (process.name : "cmd.exe" and process.args : "?:\\WINDOWS\\system32\\powercfg.exe" and process.args : "?:\\WINDOWS\\inf\\PowerPlan.log") and

  not (process.name : "regsvr32.exe" and process.args : "?:\\Windows\\Help\\OEM\\scripts\\checkmui.dll") and

  not (process.name : "cmd.exe" and
       process.parent.executable : ("?:\\Windows\\System32\\oobe\\windeploy.exe",
                                    "?:\\Program Files (x86)\\ossec-agent\\wazuh-agent.exe",
                                    "?:\\Windows\\System32\\igfxCUIService.exe",
                                    "?:\\Windows\\Temp\\IE*.tmp\\IE*-support\\ienrcore.exe"))

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
Technique:
- Name: Command and Scripting Interpreter
- ID: T1059
- Reference URL: https://attack.mitre.org/techniques/T1059/
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Masquerading
- ID: T1036
- Reference URL: https://attack.mitre.org/techniques/T1036/
Sub-technique:
- Name: Match Legitimate Name or Location
- ID: T1036.005
- Reference URL: https://attack.mitre.org/techniques/T1036/005/

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