Sigma rule: Potential Persistence Via Powershell Search Order Hijacking - Task

Rule

Title

Potential Persistence Via Powershell Search Order Hijacking - Task

Status

test

Level

high

Author

pH-T (Nextron Systems), Florian Roth (Nextron Systems)

Date

2022-04-08

Modified

2023-02-03

File

rules/windows/process_creation/proc_creation_win_schtasks_powershell_persistence.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious powershell execution via a schedule task where the command ends with an suspicious flags to hide the powershell instance instead of executeing scripts or commands. This could be a sign of persistence via PowerShell "Get-Variable" technique as seen being used in Colibri Loader

Log source

product

windows

category

process_creation

Detection

selection:
    ParentImage: 'C:\WINDOWS\System32\svchost.exe'
    ParentCommandLine|contains|all:
        - '-k netsvcs'
        - '-s Schedule'
    CommandLine|endswith:
        - ' -windowstyle hidden'
        - ' -w hidden'
        - ' -ep bypass'
        - ' -noni'
condition: selection

False positives (as the rule lists them)

• Unknown

Tags

• attack.privilege-escalation
• attack.execution
• attack.persistence
• attack.t1053.005
• attack.t1059.001

MITRE ATT&CK ids this rule names

• T1053.005
• T1059.001

Related rules

• 6e8811ee-90ba-441e-8486-5653e68b2299 (similar)

References

• https://blog.malwarebytes.com/threat-intelligence/2022/04/colibri-loader-combines-task-scheduler-and-powershell-in-clever-persistence-technique/

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_schtasks_powershell_persistence.yml