﻿---
title: Unusual Parent-Child Relationship
description: Identifies Windows programs run from unexpected parent processes. This could indicate masquerading or other strange activity on a system. Rule type: eql...
url: https://www.elastic.co/elastic/docs-builder/docs/2847/reference/security/prebuilt-rules/rules/windows/privilege_escalation_unusual_parentchild_relationship
products:
  - Elastic Security
---

# Unusual Parent-Child Relationship
Identifies Windows programs run from unexpected parent processes. This could indicate masquerading or other strange
activity on a system.
**Rule type**: eql
**Rule indices**:
- endgame-*
- logs-crowdstrike.fdr*
- logs-endpoint.events.process-*
- logs-m365_defender.event-*
- logs-sentinel_one_cloud_funnel.*
- logs-system.security*
- logs-windows.forwarded*
- logs-windows.sysmon_operational-*
- winlogbeat-*

**Rule Severity**: medium
**Risk Score**: 47
**Runs every**: 
**Searches indices from**: `now-9m`
**Maximum alerts per execution**: 100
**References**:
- [[https://github.com/sbousseaden/Slides/blob/master/Hunting%20MindMaps/PNG/Windows%20Processes%20TH.map.png](https://github.com/sbousseaden/Slides/blob/master/Hunting%20MindMaps/PNG/Windows%20Processes%20TH.map.png)](https://github.com/sbousseaden/Slides/blob/master/Hunting%20MindMaps/PNG/Windows%20Processes%20TH.map.png)
- [[https://www.andreafortuna.org/2017/06/15/standard-windows-processes-a-brief-reference/](https://www.andreafortuna.org/2017/06/15/standard-windows-processes-a-brief-reference/)](https://www.andreafortuna.org/2017/06/15/standard-windows-processes-a-brief-reference/)
- [[https://www.elastic.co/security-labs/elastic-security-labs-steps-through-the-r77-rootkit](https://www.elastic.co/security-labs/elastic-security-labs-steps-through-the-r77-rootkit)](https://www.elastic.co/security-labs/elastic-security-labs-steps-through-the-r77-rootkit)

**Tags**:
- Domain: Endpoint
- OS: Windows
- Use Case: Threat Detection
- Tactic: Privilege Escalation
- Resources: Investigation Guide
- Data Source: Elastic Endgame
- Data Source: Elastic Defend
- Data Source: Windows Security Event Logs
- Data Source: Microsoft Defender for Endpoint
- Data Source: Sysmon
- Data Source: SentinelOne
- Data Source: Crowdstrike

**Version**: 319
**Rule authors**:
- Elastic

**Rule license**: Elastic License v2

## Investigation guide


## Triage and analysis


### Investigating Unusual Parent-Child Relationship

Windows internal/system processes have some characteristics that can be used to spot suspicious activities. One of these characteristics is parent-child relationships. These relationships can be used to baseline the typical behavior of the system and then alert on occurrences that don't comply with the baseline.
This rule uses this information to spot suspicious parent and child processes.> **Note**:
This investigation guide uses the [Osquery Markdown Plugin](https://www.elastic.co/guide/en/security/current/invest-guide-run-osquery.html) introduced in Elastic Stack version 8.5.0. Older Elastic Stack versions will display unrendered Markdown in this guide.

#### Possible investigation steps

- Investigate the process execution chain (parent process tree) for unknown processes. Examine their executable files for prevalence, whether they are located in expected locations, and if they are signed with valid digital signatures.
- Investigate other alerts associated with the user/host during the past 48 hours.
- Investigate any abnormal behavior by the subject process such as network connections, registry or file modifications, and any spawned child processes.
- Examine the host for derived artifacts that indicate suspicious activities:
  - Analyze the process executable using a private sandboxed analysis system.
- Observe and collect information about the following activities in both the sandbox and the alert subject host:
  - Attempts to contact external domains and addresses.
  - Use the Elastic Defend network events to determine domains and addresses contacted by the subject process by filtering by the process' `process.entity_id`.
- Examine the DNS cache for suspicious or anomalous entries.
  - $osquery_0
- Use the Elastic Defend registry events to examine registry keys accessed, modified, or created by the related processes in the process tree.
- Examine the host services for suspicious or anomalous entries.
  - $osquery_1
- $osquery_2
- $osquery_3
- Retrieve the files' SHA-256 hash values using the PowerShell `Get-FileHash` cmdlet and search for the existence and reputation of the hashes in resources like VirusTotal, Hybrid-Analysis, CISCO Talos, Any.run, etc.
- Investigate potentially compromised accounts. Analysts can do this by searching for login events (for example, 4624) to the target host after the registry modification.


### False positive analysis

- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.


### Response and remediation

- Initiate the incident response process based on the outcome of the triage.
- Isolate the involved host to prevent further post-compromise behavior.
- If the triage identified malware, search the environment for additional compromised hosts.
  - Implement temporary network rules, procedures, and segmentation to contain the malware.
- Stop suspicious processes.
- Immediately block the identified indicators of compromise (IoCs).
- Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system.
- Remove and block malicious artifacts identified during triage.
- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
- Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the mean time to respond (MTTR).


## Rule Query

```eql
process where host.os.type == "windows" and event.type == "start" and
process.parent.name != null and
 (
   /* suspicious parent processes */
   (process.name:"autochk.exe" and not process.parent.name:"smss.exe") or
   (process.name:("fontdrvhost.exe", "dwm.exe") and not process.parent.name:("wininit.exe", "winlogon.exe", "dwm.exe")) or
   (process.name:("consent.exe", "RuntimeBroker.exe", "TiWorker.exe") and not process.parent.name:("svchost.exe", "Workplace Container Helper.exe")) or
   (process.name:"SearchIndexer.exe" and not process.parent.name:"services.exe") or
   (process.name:"SearchProtocolHost.exe" and not process.parent.name:("SearchIndexer.exe", "dllhost.exe")) or
   (process.name:"dllhost.exe" and not process.parent.name:("services.exe", "svchost.exe")) or
   (process.name:"smss.exe" and not process.parent.name:("System", "smss.exe")) or
   (process.name:"csrss.exe" and not process.parent.name:("smss.exe", "svchost.exe")) or
   (process.name:"wininit.exe" and not process.parent.name:"smss.exe") or
   (process.name:"winlogon.exe" and not process.parent.name:"smss.exe") or
   (process.name:("lsass.exe", "LsaIso.exe") and not process.parent.name:"wininit.exe") or
   (process.name:"LogonUI.exe" and not process.parent.name:("wininit.exe", "winlogon.exe")) or
   (process.name:"services.exe" and not process.parent.name:"wininit.exe") or
   (process.name:"svchost.exe" and not process.parent.name:("MsMpEng.exe", "services.exe", "svchost.exe")) or
   (process.name:"spoolsv.exe" and not process.parent.name:("services.exe", "Workplace Starter.exe")) or
   (process.name:"taskhost.exe" and not process.parent.name:("services.exe", "svchost.exe", "ngentask.exe")) or
   (process.name:"taskhostw.exe" and not process.parent.name:("services.exe", "svchost.exe")) or
   (process.name:"userinit.exe" and not process.parent.name:("dwm.exe", "winlogon.exe", "KUsrInit.exe")) or
   (process.name:("wmiprvse.exe", "wsmprovhost.exe", "winrshost.exe") and not process.parent.name:"svchost.exe") or
   /* suspicious child processes */
   (process.parent.name:("SearchProtocolHost.exe", "taskhost.exe", "csrss.exe") and not process.name:("werfault.exe", "wermgr.exe", "WerFaultSecure.exe", "conhost.exe", "ngentask.exe")) or
   (process.parent.name:"autochk.exe" and not process.name:("chkdsk.exe", "doskey.exe", "WerFault.exe")) or
   (process.parent.name:"smss.exe" and not process.name:("autochk.exe", "smss.exe", "csrss.exe", "wininit.exe", "winlogon.exe", "setupcl.exe", "WerFault.exe", "wpbbin.exe", "PvsVmBoot.exe", "SophosNA.exe", "omnissa-ic-nga.exe", "icarus_rvrt.exe", "poqexec.exe")) or
   (process.parent.name:"wermgr.exe" and not process.name:("WerFaultSecure.exe", "wermgr.exe", "WerFault.exe")) or
   (process.parent.name:"conhost.exe" and not process.name:("mscorsvw.exe", "wermgr.exe", "WerFault.exe", "WerFaultSecure.exe"))
  )
```

**Framework:** MITRE ATT&CK
- Tactic:
  - Name: Privilege Escalation
- Id: TA0004
- Reference URL: [[https://attack.mitre.org/tactics/TA0004/](https://attack.mitre.org/tactics/TA0004/)](https://attack.mitre.org/tactics/TA0004/)
- Technique:
  - Name: Process Injection
- Id: T1055
- Reference URL: [[https://attack.mitre.org/techniques/T1055/](https://attack.mitre.org/techniques/T1055/)](https://attack.mitre.org/techniques/T1055/)
- Sub Technique:
  - Name: Process Hollowing
- Id: T1055.012
- Reference URL: [[https://attack.mitre.org/techniques/T1055/012/](https://attack.mitre.org/techniques/T1055/012/)](https://attack.mitre.org/techniques/T1055/012/)