Scheduled Task Creation or Modification Containing Suspicious Scripts, Extensions or User Writable Paths

Hypothesis and description

Detection of the creation or modification of Scheduled Tasks with a suspicious script, extension or user writable path. Attackers may create or modify Scheduled Tasks for the persistent execution of malicious code. This detection focuses at the same time on EventIDs 4688 and 1 with process creation (SCHTASKS) and EventID 4698, 4702 for Scheduled Task creation/modification event log.

Platforms: Windows
Domain: Host
Subtypes: Process
Submitted: 2021-12-04
Contributors: Lucas Heiligenstein

ATT&CK coverage

Technique	Tactics	Coverage
T1053 Scheduled Task/JobT1053.005	Execution, Persistence, Privilege Escalation	Medium

1 technique, 2 ATT&CK ids including sub-techniques. Links open MITRE ATT&CK.

T1053Scheduled Task/Job
.005 Scheduled Task

Marked techniques are also explained, with detection notes and certification relevance, on our interactive ATT&CK map.

D3FEND techniques MITRE maps to this analytic

D3-PSA Process Spawn Analysis

Data model references

Fields from the CAR data model (object/action/field) the analytic reads.

process/create/command_line

Pseudocode and implementations

PseudocodeCreation of Suspicious Scheduled TasksData model: CAR native

This detects the creation of suspicious scheduled tasks, either via a new process (command line) or direct through the corresponding Windows EIDs.

processes = search Process:create
susp_tasks_processes = filter processes where command_line CONTAINS("*SCHTASKS*") AND (command_line CONTAINS("*/CREATE*") OR command_line CONTAINS("*/CHANGE*")) AND (command_line CONTAINS("*.cmd*") OR command_line CONTAINS("*.ps1*") OR command_line CONTAINS("*.vbs*") OR command_line CONTAINS("*.py*") OR command_line CONTAINS("*.js*") OR command_line CONTAINS("*.exe*") OR command_line CONTAINS("*.bat*") OR (command_line CONTAINS("*javascript*") OR command_line CONTAINS("*powershell*") OR command_line CONTAINS("*wmic*") OR command_line CONTAINS("*rundll32*") OR command_line CONTAINS("*cmd*") OR command_line CONTAINS("*cscript*") OR command_line CONTAINS("*wscript*") OR command_line CONTAINS("*regsvr32*") OR command_line CONTAINS("*mshta*") OR command_line CONTAINS("*bitsadmin*") OR command_line CONTAINS("*certutil*") OR command_line CONTAINS("*msiexec*") OR command_line CONTAINS("*javaw*") OR (command_line CONTAINS("*%APPDATA%*") OR command_line CONTAINS("*\\AppData\\Roaming*") OR command_line CONTAINS("*%PUBLIC%*") OR command_line CONTAINS("*C:\\Users\\Public*") OR command_line CONTAINS("*%ProgramData%*") OR command_line CONTAINS("*C:\\ProgramData*") OR command_line CONTAINS("*%TEMP%*") OR command_line CONTAINS("*\\AppData\\Local\\Temp*") OR command_line CONTAINS("*\\Windows\\PLA\\System*") OR command_line CONTAINS("*\\tasks*") OR command_line CONTAINS("*\\Registration\\CRMLog*") OR command_line CONTAINS("*\\FxsTmp*") OR command_line CONTAINS("*\\spool\\drivers\\color*") OR command_line CONTAINS("*\\tracing*"))))
tasks = search Task:create
susp_tasks = filter tasks where (task_content CONTAINS("*.cmd*") OR task_content CONTAINS("*.ps1*") OR task_content CONTAINS("*.vbs*") OR task_content CONTAINS("*.py*") OR task_content CONTAINS("*.js*") OR task_content CONTAINS("*.exe*") OR task_content CONTAINS("*.bat*") OR (task_content CONTAINS("*javascript*") OR task_content CONTAINS("*powershell*") OR task_content CONTAINS("*wmic*") OR task_content CONTAINS("*rundll32*") OR task_content CONTAINS("*cmd*") OR task_content CONTAINS("*cscript*") OR task_content CONTAINS("*wscript*") OR task_content CONTAINS("*regsvr32*") OR task_content CONTAINS("*mshta*") OR task_content CONTAINS("*bitsadmin*") OR task_content CONTAINS("*certutil*") OR task_content CONTAINS("*msiexec*") OR task_content CONTAINS("*javaw*") OR (task_content CONTAINS("*%APPDATA%*") OR task_content CONTAINS("*\\AppData\\Roaming*") OR task_content CONTAINS("*%PUBLIC%*") OR task_content CONTAINS("*C:\\Users\\Public*") OR task_content CONTAINS("*%ProgramData%*") OR task_content CONTAINS("*C:\\ProgramData*") OR task_content CONTAINS("*%TEMP%*") OR task_content CONTAINS("*\\AppData\\Local\\Temp*") OR task_content CONTAINS("*\\Windows\\PLA\\System*") OR task_content CONTAINS("*\\tasks*") OR task_content CONTAINS("*\\Registration\\CRMLog*") OR task_content CONTAINS("*\\FxsTmp*") OR task_content CONTAINS("*\\spool\\drivers\\color*") OR task_content CONTAINS("*\\tracing*"))))
output susp_tasks_processes, susp_tasks

SplunkSplunk Search - Scheduled Task creation or modification containing suspicious script, extension or user writable path.

This is a Splunk representation of the above pseudocode search.

(((EventCode="4688" OR EventCode="1") CommandLine="*SCHTASKS*" (CommandLine="*/CREATE*" OR CommandLine="*/CHANGE*")) ((CommandLine="*.cmd*" OR CommandLine="*.ps1*" OR CommandLine="*.vbs*" OR CommandLine="*.py*" OR CommandLine="*.js*" OR CommandLine="*.exe*" OR CommandLine="*.bat*") OR (CommandLine="*javascript*" OR CommandLine="*powershell*" OR CommandLine="*wmic*" OR CommandLine="*rundll32*" OR CommandLine="*cmd*" OR CommandLine="*cscript*" OR CommandLine="*wscript*" OR CommandLine="*regsvr32*" OR CommandLine="*mshta*" OR CommandLine="*bitsadmin*" OR CommandLine="*certutil*" OR CommandLine="*msiexec*" OR CommandLine="*javaw*") OR (CommandLine="*%APPDATA%*" OR CommandLine="*\\AppData\\Roaming*" OR CommandLine="*%PUBLIC%*" OR CommandLine="*C:\\Users\\Public*" OR CommandLine="*%ProgramData%*" OR CommandLine="*C:\\ProgramData*" OR CommandLine="*%TEMP%*" OR CommandLine="*\\AppData\\Local\\Temp*" OR CommandLine="*\\Windows\\PLA\\System*" OR CommandLine="*\\tasks*" OR CommandLine="*\\Registration\\CRMLog*" OR CommandLine="*\\FxsTmp*" OR CommandLine="*\\spool\\drivers\\color*" OR CommandLine="*\\tracing*"))) OR ((EventCode="4698" OR EventCode="4702") ((TaskContent="*.cmd*" OR TaskContent="*.ps1*" OR TaskContent="*.vbs*" OR TaskContent="*.py*" OR TaskContent="*.js*" OR TaskContent="*.exe*" OR TaskContent="*.bat*") OR (TaskContent="*javascript*" OR TaskContent="*powershell*" OR TaskContent="*wmic*" OR TaskContent="*rundll32*" OR TaskContent="*cmd*" OR TaskContent="*cscript*" OR TaskContent="*wscript*" OR TaskContent="*regsvr32*" OR TaskContent="*mshta*" OR TaskContent="*bitsadmin*" OR TaskContent="*certutil*" OR TaskContent="*msiexec*" OR TaskContent="*javaw*") OR (TaskContent="*%APPDATA%*" OR TaskContent="*\\AppData\\Roaming*" OR TaskContent="*%PUBLIC%*" OR TaskContent="*C:\\Users\\Public*" OR TaskContent="*%ProgramData%*" OR TaskContent="*C:\\ProgramData*" OR TaskContent="*%TEMP%*" OR TaskContent="*\\AppData\\Local\\Temp*" OR TaskContent="*\\Windows\\PLA\\System*" OR TaskContent="*\\tasks*" OR TaskContent="*\\Registration\\CRMLog*" OR TaskContent="*\\FxsTmp*" OR TaskContent="*\\spool\\drivers\\color*" OR TaskContent="*\\tracing*")))

ElasticElastic Search - Scheduled Task creation or modification containing suspicious script, extension or user writable path.

This is an ElasticSearch representation of the above pseudocode search.

((winlog.event_id:("4688" OR "1") AND process.command_line:*SCHTASKS* AND process.command_line:(*\/CREATE* OR *\/CHANGE*)) AND (process.command_line:(*.cmd* OR *.ps1* OR *.vbs* OR *.py* OR *.js* OR *.exe* OR *.bat*) OR process.command_line:(*javascript* OR *powershell* OR *wmic* OR *rundll32* OR *cmd* OR *cscript* OR *wscript* OR *regsvr32* OR *mshta* OR *bitsadmin* OR *certutil* OR *msiexec* OR *javaw*) OR process.command_line:(*%APPDATA%* OR *\\AppData\\Roaming* OR *%PUBLIC%* OR *C\:\\Users\\Public* OR *%ProgramData%* OR *C\:\\ProgramData* OR *%TEMP%* OR *\\AppData\\Local\\Temp* OR *\\Windows\\PLA\\System* OR *\\tasks* OR *\\Registration\\CRMLog* OR *\\FxsTmp* OR *\\spool\\drivers\\color* OR *\\tracing*))) OR (winlog.event_id:("4698" OR "4702") AND (winlog.event_data.TaskContent:(*.cmd* OR *.ps1* OR *.vbs* OR *.py* OR *.js* OR *.exe* OR *.bat*) OR winlog.event_data.TaskContent:(*javascript* OR *powershell* OR *wmic* OR *rundll32* OR *cmd* OR *cscript* OR *wscript* OR *regsvr32* OR *mshta* OR *bitsadmin* OR *certutil* OR *msiexec* OR *javaw*) OR winlog.event_data.TaskContent:(*%APPDATA%* OR *\\AppData\\Roaming* OR *%PUBLIC%* OR *C\:\\Users\\Public* OR *%ProgramData%* OR *C\:\\ProgramData* OR *%TEMP%* OR *\\AppData\\Local\\Temp* OR *\\Windows\\PLA\\System* OR *\\tasks* OR *\\Registration\\CRMLog* OR *\\FxsTmp* OR *\\spool\\drivers\\color* OR *\\tracing*)))

LogPointLogPoint Search - Scheduled Task creation or modification containing suspicious script, extension or user writable path.

This is a LogPoint representation of the above pseudocode search.

((event_id IN ["4688", "1"] CommandLine="*SCHTASKS*" CommandLine IN ["*/CREATE*", "*/CHANGE*"]) (CommandLine IN ["*.cmd*", "*.ps1*", "*.vbs*", "*.py*", "*.js*", "*.exe*", "*.bat*"] OR CommandLine IN ["*javascript*", "*powershell*", "*wmic*", "*rundll32*", "*cmd*", "*cscript*", "*wscript*", "*regsvr32*", "*mshta*", "*bitsadmin*", "*certutil*", "*msiexec*", "*javaw*"] OR CommandLine IN ["*%APPDATA%*", "*\\AppData\\Roaming*", "*%PUBLIC%*", "*C:\\Users\\Public*", "*%ProgramData%*", "*C:\\ProgramData*", "*%TEMP%*", "*\\AppData\\Local\\Temp*", "*\\Windows\\PLA\\System*", "*\\tasks*", "*\\Registration\\CRMLog*", "*\\FxsTmp*", "*\\spool\\drivers\\color*", "*\\tracing*"])) OR (event_id IN ["4698", "4702"] (TaskContent IN ["*.cmd*", "*.ps1*", "*.vbs*", "*.py*", "*.js*", "*.exe*", "*.bat*"] OR TaskContent IN ["*javascript*", "*powershell*", "*wmic*", "*rundll32*", "*cmd*", "*cscript*", "*wscript*", "*regsvr32*", "*mshta*", "*bitsadmin*", "*certutil*", "*msiexec*", "*javaw*"] OR TaskContent IN ["*%APPDATA%*", "*\\AppData\\Roaming*", "*%PUBLIC%*", "*C:\\Users\\Public*", "*%ProgramData%*", "*C:\\ProgramData*", "*%TEMP%*", "*\\AppData\\Local\\Temp*", "*\\Windows\\PLA\\System*", "*\\tasks*", "*\\Registration\\CRMLog*", "*\\FxsTmp*", "*\\spool\\drivers\\color*", "*\\tracing*"]))

Across MITRE's defensive frameworks

Linked through the 1 ATT&CK technique above.

Counter with D3FEND

Defensive techniques MITRE D3FEND maps to the same ATT&CK techniques.

15 more in the full list

View CAR-2021-12-001 on car.mitre.org