Sigma rule: Suspicious CustomShellHost Execution

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-150fc5873014, updated 2025-10-29T00:00:00.000Z.

Rule

Title
Suspicious CustomShellHost Execution
Status
test
Level
high
Author
Nasreddine Bencherchali (Nextron Systems)
Date
2022-08-19
Modified
2025-10-29
File
rules/windows/process_creation/proc_creation_win_customshellhost_susp_exec.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the execution of CustomShellHost.exe where the child isn't located in 'C:\Windows\explorer.exe'. CustomShellHost is a known LOLBin that can be abused by attackers for defense evasion techniques.

Log source

product
windows
category
process_creation

Detection

selection:
    ParentImage|endswith: '\CustomShellHost.exe'
filter_main_explorer:
    Image: 'C:\Windows\explorer.exe'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

  • False positives are unlikely, investigate matches carefully.

Tags

  • attack.stealth
  • attack.t1216

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_customshellhost_susp_exec.yml

Sources and licences

  • SigmaHQ

    "Suspicious CustomShellHost Execution" by Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_customshellhost_susp_exec.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Suspicious CustomShellHost Execution",
entity page, dataset version ref-150fc5873014, updated 2025-10-29T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/84b14121-9d14-416e-800b-f3b829c5a14d (accessed 2026-11-03).
Underlying source: SigmaHQ rule 84b14121-9d14-416e-800b-f3b829c5a14d, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.