Conhost Spawned By Suspicious Parent Processedit

Detects when the Console Window Host (conhost.exe) process is spawned by a suspicious parent process, which could be indicative of code injection.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-windows.*
  • endgame-*

Severity: high

Risk score: 73

Runs every: 5 minutes

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

Maximum alerts per execution: 100



  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Execution
  • Investigation Guide
  • Elastic Endgame

Version: 102 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 8.6.0

Rule authors: Elastic

Rule license: Elastic License v2

Investigation guideedit

## Triage and analysis

### Investigating Conhost Spawned By Suspicious Parent Process

The Windows Console Host, or `conhost.exe`, is both the server application for all of the Windows Console APIs as well as
the classic Windows user interface for working with command-line applications.

Attackers often rely on custom shell implementations to avoid using built-in command interpreters like `cmd.exe` and
`PowerShell.exe` and bypass application allowlisting and security features. Attackers commonly inject these implementations into
legitimate system processes.

#### 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 abnormal behaviors observed by the subject process, such as network connections, registry or file
modifications, and any spawned child processes.
- Investigate other alerts associated with the user/host during the past 48 hours.
- Inspect the host for suspicious or abnormal behavior in the alert timeframe.
- Retrieve the parent process executable and determine if it is malicious:
  - Use a private sandboxed malware analysis system to perform analysis.
    - Observe and collect information about the following activities:
      - Attempts to contact external domains and addresses.
      - File and registry access, modification, and creation activities.
      - Service creation and launch activities.
      - Scheduled task creation.
  - Use the PowerShell `Get-FileHash` cmdlet to get the files' SHA-256 hash values.
    - Search for the existence and reputation of the hashes in resources like VirusTotal, Hybrid-Analysis, CISCO Talos,, etc.

### False positive analysis

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

### Related rules

- Suspicious Process from Conhost - 28896382-7d4f-4d50-9b72-67091901fd26
- Suspicious PowerShell Engine ImageLoad - 852c1f19-68e8-43a6-9dce-340771fe1be3

### Response and remediation

- Initiate the incident response process based on the outcome of the triage.
- Isolate the involved hosts 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.
- Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are
identified. Reset passwords for these accounts and other potentially compromised credentials, such as email, business
systems, and web services.
- 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 queryedit

process where event.type == "start" and : "conhost.exe"
and : ("lsass.exe", "services.exe", "smss.exe",
"winlogon.exe", "explorer.exe", "dllhost.exe", "rundll32.exe",
"regsvr32.exe", "userinit.exe", "wininit.exe", "spoolsv.exe",
"ctfmon.exe") and not ( : "rundll32.exe" and
process.parent.args : ("?:\\Windows\\Installer\\MSI*.tmp,zzzzInvokeMan

Threat mappingedit


Rule version historyedit

Version 102 (8.6.0 release)
  • Formatting only
Version 101 (8.5.0 release)
  • Updated query, changed from:

    process where event.type in ("start", "process_started") and : "conhost.exe" and :
    ("svchost.exe", "lsass.exe", "services.exe", "smss.exe",
    "winlogon.exe", "explorer.exe",
    "dllhost.exe", "rundll32.exe", "regsvr32.exe", "userinit.exe",
    "wininit.exe", "spoolsv.exe", "wermgr.exe",
    "csrss.exe", "ctfmon.exe")
Version 8 (8.4.0 release)
  • Formatting only
Version 6 (8.3.0 release)
  • Formatting only
Version 5 (8.2.0 release)
  • Formatting only
Version 4 (7.13.0 release)
  • Updated query, changed from:

    event.category:process and event.type:(start or process_started) and and or
    lsass.exe or services.exe or smss.exe or winlogon.exe or explorer.exe
    or dllhost.exe or rundll32.exe or regsvr32.exe or userinit.exe or
    wininit.exe or spoolsv.exe or wermgr.exe or csrss.exe or ctfmon.exe)
Version 3 (7.12.0 release)
  • Formatting only
Version 2 (7.11.2 release)
  • Formatting only