Detectionhightest

Suspicious Modification Of Scheduled Tasks

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

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Launch

Nasreddine Bencherchali (Nextron Systems)Created Thu Jul 28Updated Fri Nov 181c0e41cd-21bb-4433-9acc-4a2cd6367b9bwindows

Log Source

WindowsProcess Creation

ProductWindows← raw: windows

CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic

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_*