Office Product Spawning Windows Script Host
Description
The following analytic will identify a Windows Office Product spawning WScript.exe or CScript.exe. Tuning may be required based on legitimate application usage that may spawn scripts from an Office product.
- Type: TTP
- Product: Splunk Behavioral Analytics
- Datamodel: Endpoint_Processes
- Last Updated: 2023-02-15
- Author: Michael Haag, Splunk
- ID: 3ea3851a-8736-41a0-bc09-7e4485b48fa6
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- PR.PT
- DE.CM
CIS20
- CIS 8
CVE
Search
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| from read_ssa_enriched_events()
| eval timestamp=parse_long(ucast(map_get(input_event, "_time"), "string", null)), cmd_line=lower(ucast(map_get(input_event, "process"), "string", null)), process_name=lower(ucast(map_get(input_event, "process_name"), "string", null)), process_path=ucast(map_get(input_event, "process_path"), "string", null), parent_process_name=lower(ucast(map_get(input_event, "parent_process_name"), "string", null)), event_id=ucast(map_get(input_event, "event_id"), "string", null)
| where cmd_line IS NOT NULL AND process_name IS NOT NULL AND parent_process_name IS NOT NULL
| where (like(parent_process_name, "%\\\\winword.exe") OR like(parent_process_name, "%\\\\excel.exe") OR like(parent_process_name, "%\\\\powerpnt.exe") OR like(parent_process_name, "%\\\\mspub.exe") OR like(parent_process_name, "%\\\\visio.exe") OR like(parent_process_name, "%\\\\msaccess.exe")) AND (process_name="wscript.exe" OR process_name="cscript.exe")
| eval start_time=timestamp, end_time=timestamp, entities=mvappend(ucast(map_get(input_event, "dest_user_id"), "string", null), ucast(map_get(input_event, "dest_device_id"), "string", null)), body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name", process_name, "parent_process_name", parent_process_name, "process_path", process_path])
| into write_ssa_detected_events();
Macros
The SPL above uses the following Macros:
office_product_spawning_windows_script_host_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Required fields
List of fields required to use this analytic.
- _time
- dest_device_id
- process_name
- parent_process_name
- process_path
- dest_user_id
- process
How To Implement
To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
Known False Positives
False positives may be present based on macro based approved documents in the organization. Filtering may be needed.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
63.0 | 70 | 90 | A Microsoft office parent process $parent_process_name$ has spawned a suspicious child process $process_name$ on host $dest$. |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
Reference
Test Dataset
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
source | version: 2