Sigma rule: Suspicious Modification Of Scheduled Tasks

Rule

Title

Suspicious Modification Of Scheduled Tasks

Status

test

Level

high

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2022-07-28

Modified

2022-11-18

File

rules/windows/process_creation/proc_creation_win_schtasks_change.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects when an attacker tries to modify an already existing scheduled tasks to run from a suspicious location
Attackers can create a simple looking task in order to avoid detection on creation as it's often the most focused on
Instead they modify the task after creation to include their malicious payload

Log source

product

windows

category

process_creation

Detection

selection_schtasks:
    Image|endswith: '\schtasks.exe'
    CommandLine|contains|all:
        - ' /Change '
        - ' /TN '
selection_susp_locations:
    CommandLine|contains:
        - '\AppData\Local\Temp'
        - '\AppData\Roaming\'
        - '\Users\Public\'
        - '\WINDOWS\Temp\'
        - '\Desktop\'
        - '\Downloads\'
        - '\Temporary Internet'
        - 'C:\ProgramData\'
        - 'C:\Perflogs\'
        - '%ProgramData%'
        - '%appdata%'
        - '%comspec%'
        - '%localappdata%'
selection_susp_images:
    CommandLine|contains:
        - 'regsvr32'
        - 'rundll32'
        - 'cmd /c '
        - 'cmd /k '
        - 'cmd /r '
        - 'cmd.exe /c '
        - 'cmd.exe /k '
        - 'cmd.exe /r '
        - 'powershell'
        - 'mshta'
        - 'wscript'
        - 'cscript'
        - 'certutil'
        - 'bitsadmin'
        - 'bash.exe'
        - 'bash '
        - 'scrcons'
        - 'wmic '
        - 'wmic.exe'
        - 'forfiles'
        - 'scriptrunner'
        - 'hh.exe'
        - 'hh '
condition: all of selection_*

False positives (as the rule lists them)

• Unknown

Tags

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

MITRE ATT&CK ids this rule names

• T1053.005

Related rules

• 614cf376-6651-47c4-9dcc-6b9527f749f4 (similar)

References

• Internal Research
• https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/schtasks

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_change.yml