Sigma rule: Windows Shell/Scripting Processes Spawning Suspicious Programs

Rule

Title

Windows Shell/Scripting Processes Spawning Suspicious Programs

Status

test

Level

high

Author

Florian Roth (Nextron Systems), Tim Shelton

Date

2018-04-06

Modified

2023-05-23

File

rules/windows/process_creation/proc_creation_win_susp_shell_spawn_susp_program.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious child processes of a Windows shell and scripting processes such as wscript, rundll32, powershell, mshta...etc.

Log source

product

windows

category

process_creation

Detection

selection:
    ParentImage|endswith:
        - '\mshta.exe'
        - '\powershell.exe'
        - '\pwsh.exe'
        # - '\cmd.exe'  # too many false positives
        - '\rundll32.exe'
        - '\cscript.exe'
        - '\wscript.exe'
        - '\wmiprvse.exe'
        - '\regsvr32.exe'
    Image|endswith:
        - '\schtasks.exe'
        - '\nslookup.exe'
        - '\certutil.exe'
        - '\bitsadmin.exe'
        - '\mshta.exe'
filter_ccmcache:
    CurrentDirectory|contains: '\ccmcache\'
filter_amazon:
    ParentCommandLine|contains:
        # FP - Amazon Workspaces
        - '\Program Files\Amazon\WorkSpacesConfig\Scripts\setup-scheduledtask.ps1'
        - '\Program Files\Amazon\WorkSpacesConfig\Scripts\set-selfhealing.ps1'
        - '\Program Files\Amazon\WorkSpacesConfig\Scripts\check-workspacehealth.ps1'
        - '\nessus_' # Tenable/Nessus VA Scanner
filter_nessus:
    CommandLine|contains: '\nessus_' # Tenable/Nessus VA Scanner
filter_sccm_install:
    ParentImage|endswith: '\mshta.exe'
    Image|endswith: '\mshta.exe'
    ParentCommandLine|contains|all:
        - 'C:\MEM_Configmgr_'
        - '\splash.hta'
        - '{1E460BD7-F1C3-4B2E-88BF-4E770A288AF5}'
    CommandLine|contains|all:
        - 'C:\MEM_Configmgr_'
        - '\SMSSETUP\BIN\'
        - '\autorun.hta'
        - '{1E460BD7-F1C3-4B2E-88BF-4E770A288AF5}'
condition: selection and not 1 of filter_*

False positives (as the rule lists them)

• Administrative scripts
• Microsoft SCCM

Tags

• attack.execution
• attack.stealth
• attack.t1059.005
• attack.t1059.001
• attack.t1218

MITRE ATT&CK ids this rule names

• T1059.001
• T1059.005
• T1218

References

• https://mgreen27.github.io/posts/2018/04/02/DownloadCradle.html

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_susp_shell_spawn_susp_program.yml